Esercizio 1

Dati sugli indiani

data(PimaIndiansDiabetes2)
df = PimaIndiansDiabetes2 %>% tibble
df

Analizzo quali sono le colonne con più valori mancanti(NA).

DataExplorer::plot_missing(df)

Provo a vedere anche quali sono le variabili più correlate per capire se sia necessario conservare o meno insulin e triceps.

DataExplorer::plot_correlation(df %>% na.omit)

scoreNA = sapply(1:ncol(df),function(c) sum(is.na(df[,c])))
names(scoreNA) = names(df)
scoreNA
## pregnant  glucose pressure  triceps  insulin     mass pedigree      age 
##        0        5       35      227      374       11        0        0 
## diabetes 
##        0

Un altro metodo può essere quello di costruire diversi GLM ma con diversi parametri inclusi e allo stesso tempo diversi dati, in quanto quando includo alcuni parametri non potrò usare i dati che non possiedono i valori per quei determinati parametri. Questa procedura risulta essere però, molto laboriosa.

Si procede allora alla creazione di una funzione, che come stepAIC della libreria MASS in versione backward, parte da un modello contenente tutte le variabili e successivamente rimuove quelle con più NA. La funzione creata è stata generalizzata per lavorare su diversi modelli, non solo GLM, ma anche LM e GAM. Ha, tuttavia, molte limitazioni, come l’incapacità d inserire splines, polinomiali e simili sulle variabili indipendenti. Un’altra limitazione è la mancanza di un partizionamento dei dati e successivamente di un metodo di validazione del modello.

Infine, eseguendo la funzione, il modello migliore secondo il criterio d’informazione di Akaike risulta essere il primo, ovvero il modello completo.

eliminaVariabiliNA = function(funzioneModello = glm,
                              variabileRisposta,
                              dataframe,
                              famiglia,
                              variabiliFunzione = new.env(),
                              modelli = new.env())
{
  if(length(variabiliFunzione$passo) == 0) # passo 0
  {
    variabiliFunzione$passo = 0
    
    # costruisco una tabella con il numero di NA per ciascua variabile indipendente
    colonne = c(1:ncol(dataframe))[names(dataframe) != variabileRisposta]
    variabiliFunzione$scoreNA = sapply(colonne,function(c) sum(is.na(dataframe[,c])))
    names(variabiliFunzione$scoreNA) = names(dataframe)[names(dataframe)!=variabileRisposta]
    
    # definisco gli argomenti da inserire all'interno della funzione in base a ciò che ho in input, nel lm non serve la famiglia
    if(length(famiglia)>0) 
    {
      variabiliFunzione$argomenti = list(formula = as.formula(paste(variabileRisposta," ~ .")),
                                         data = dataframe, 
                                         family = famiglia)
    }else
    {
      variabiliFunzione$argomenti = list(formula = as.formula(paste(variabileRisposta," ~ .")),
                                         data = dataframe)
    }
      
    modello =  do.call(funzioneModello,list(formula = as.formula(paste(variabileRisposta," ~ .")),
                                         data = dataframe,
                                         family = binomial(link = logit)))
  }else # passo N
  {
    variabiliFunzione$argomenti$formula = modelli$formula[[variabiliFunzione$passo]]
    # rimuovo la variabile con più NA presente nel modello precedente
    modello = update(object = do.call(funzioneModello, variabiliFunzione$argomenti),
                     sprintf(". ~ . - %s",
                             deparse(as.name(names(sort(scoreNA, T)[variabiliFunzione$passo])))))
  }
  
  # incapsulo le informazioni più interessanti del modello
    modelli$AIC = append(modelli$AIC,modello$aic)
    modelli$coefficients = append(modelli$coefficients,modello$coefficients)
    modelli$formula = append(modelli$formula,modello$formula)
    modelli$deviance = append(modelli$deviance,modello$deviance)
    
    variabiliFunzione$passo = variabiliFunzione$passo + 1
    
    if(variabiliFunzione$passo < length(variabiliFunzione$scoreNA))
    {
      return(eliminaVariabiliNA(funzioneModello, 
                                variabileRisposta, 
                                dataframe, 
                                famiglia, 
                                variabiliFunzione, 
                                modelli)) # ricorsività (richiamo del passo N+1)
    }else
    {
      return(modelli)
    }
}

modGlmNa = eliminaVariabiliNA(glm,"diabetes",df,binomial(logit))

modGlmNa$AIC
## [1] 362.0212 482.3223 686.8611 715.2412 760.4366 925.2260 935.1037 954.7203

Idea

Un’idea per ottenere un modello più performante disponibile potrebbe essere quella di generare diversi modelli con diverse variabili dipendenti e in base alla variabile risposta da predire si sceglierà il modello con le features della variabile risposta.

Riempimento NA mancanti

Essendo che il modello scelto possiede molti NA conviene fare un riempimento dei NA ove possibile. Prima di fare ciò osservo come sono distribuiti i NA nelle singole osseervazioni tra le variabili. Noto che in quasi tutti i casi i NA sono “nidificati tra le variabili”, ovvero che se pressure mancherà, allora di conseguenza mancheranno anche insuline e triceps.

vis_miss(df, sort_miss = T, cluster = T)

Questa tabella aiuta a vedere le correlazioni tra le variabili e che tipo di modello sarebbe più adatto stimare.

PerformanceAnalytics::chart.Correlation(df %>% mutate_at("diabetes",as.numeric))

Il grafico sopra raffigura le correlazzioni tra variabili, le loro distribuzioni e le loro distribuzioini in funzione delle altre variabili.

Glucose

Partendo dalla variabile glucose, l’obbiettivo è quello di riempire i NA in base ai dati che abbiamo. Si nota che glucose è correlata con tutte le altre variabili, quindi presumibilmente il modello conterrà tutte le altre variabili. C’è anche multicollinearità, ma nessuna collinearità esatta, quindi sarebbe opportuno anche inserire la correlazione tra le variabili esplicative. L’obbiettivo è la previsione, più accurata possibile, degli NA e non l’interpretabilità del modello, infatti inserendo l’interazione il modello avrà molti stimatori in più. Per semplicità, è stato scelto un modello di regressione lineare.

varDip = "glucose"
colonne = names(df)[names(df) != varDip]
modGlu = lm(as.formula(paste(varDip," ~ ",paste(colonne,collapse = " * "))), data = df)
modGlu %>% summary
## 
## Call:
## lm(formula = as.formula(paste(varDip, " ~ ", paste(colonne, collapse = " * "))), 
##     data = df)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -27.086  -3.292  -0.099   3.066  74.325 
## 
## Coefficients:
##                                                                   Estimate
## (Intercept)                                                     -1.809e+04
## pregnant                                                         5.234e+03
## pressure                                                         2.404e+02
## triceps                                                          4.608e+02
## insulin                                                          1.439e+02
## mass                                                             4.947e+02
## pedigree                                                         2.876e+04
## age                                                              8.920e+02
## diabetespos                                                      6.105e+05
## pregnant:pressure                                               -6.815e+01
## pregnant:triceps                                                -1.464e+02
## pressure:triceps                                                -5.516e+00
## pregnant:insulin                                                -4.703e+01
## pressure:insulin                                                -2.093e+00
## triceps:insulin                                                 -3.825e+00
## pregnant:mass                                                   -1.441e+02
## pressure:mass                                                   -6.675e+00
## triceps:mass                                                    -1.082e+01
## insulin:mass                                                    -3.799e+00
## pregnant:pedigree                                               -1.053e+04
## pressure:pedigree                                               -3.447e+02
## triceps:pedigree                                                -4.080e+02
## insulin:pedigree                                                -2.311e+02
## mass:pedigree                                                   -8.387e+02
## pregnant:age                                                    -2.516e+02
## pressure:age                                                    -1.195e+01
## triceps:age                                                     -2.374e+01
## insulin:age                                                     -7.187e+00
## mass:age                                                        -2.516e+01
## pedigree:age                                                    -1.450e+03
## pregnant:diabetespos                                            -7.993e+04
## pressure:diabetespos                                            -7.061e+03
## triceps:diabetespos                                             -2.129e+04
## insulin:diabetespos                                             -5.565e+03
## mass:diabetespos                                                -1.869e+04
## pedigree:diabetespos                                            -1.606e+06
## age:diabetespos                                                 -2.812e+04
## pregnant:pressure:triceps                                        1.844e+00
## pregnant:pressure:insulin                                        5.969e-01
## pregnant:triceps:insulin                                         1.398e+00
## pressure:triceps:insulin                                         5.189e-02
## pregnant:pressure:mass                                           1.885e+00
## pregnant:triceps:mass                                            3.678e+00
## pressure:triceps:mass                                            1.325e-01
## pregnant:insulin:mass                                            1.294e+00
## pressure:insulin:mass                                            5.569e-02
## triceps:insulin:mass                                             8.703e-02
## pregnant:pressure:pedigree                                       1.362e+02
## pregnant:triceps:pedigree                                        2.133e+02
## pressure:triceps:pedigree                                        2.939e+00
## pregnant:insulin:pedigree                                        7.696e+01
## pressure:insulin:pedigree                                        3.047e+00
## triceps:insulin:pedigree                                         3.974e+00
## pregnant:mass:pedigree                                           3.169e+02
## pressure:mass:pedigree                                           1.031e+01
## triceps:mass:pedigree                                            1.071e+01
## insulin:mass:pedigree                                            6.420e+00
## pregnant:pressure:age                                            3.308e+00
## pregnant:triceps:age                                             6.784e+00
## pressure:triceps:age                                             2.921e-01
## pregnant:insulin:age                                             2.235e+00
## pressure:insulin:age                                             1.059e-01
## triceps:insulin:age                                              1.992e-01
## pregnant:mass:age                                                7.185e+00
## pressure:mass:age                                                3.428e-01
## triceps:mass:age                                                 6.077e-01
## insulin:mass:age                                                 1.966e-01
## pregnant:pedigree:age                                            5.247e+02
## pressure:pedigree:age                                            1.791e+01
## triceps:pedigree:age                                             2.431e+01
## insulin:pedigree:age                                             1.226e+01
## mass:pedigree:age                                                4.348e+01
## pregnant:pressure:diabetespos                                    1.009e+03
## pregnant:triceps:diabetespos                                     2.516e+03
## pressure:triceps:diabetespos                                     2.536e+02
## pregnant:insulin:diabetespos                                     1.876e+02
## pressure:insulin:diabetespos                                     6.881e+01
## triceps:insulin:diabetespos                                      1.939e+02
## pregnant:mass:diabetespos                                        3.592e+03
## pressure:mass:diabetespos                                        2.194e+02
## triceps:mass:diabetespos                                         6.011e+02
## insulin:mass:diabetespos                                         1.513e+02
## pregnant:pedigree:diabetespos                                    2.534e+05
## pressure:pedigree:diabetespos                                    2.027e+04
## triceps:pedigree:diabetespos                                     4.822e+04
## insulin:pedigree:diabetespos                                     1.275e+04
## mass:pedigree:diabetespos                                        4.759e+04
## pregnant:age:diabetespos                                         5.312e+03
## pressure:age:diabetespos                                         3.436e+02
## triceps:age:diabetespos                                          8.720e+02
## insulin:age:diabetespos                                          2.361e+02
## mass:age:diabetespos                                             8.452e+02
## pedigree:age:diabetespos                                         6.809e+04
## pregnant:pressure:triceps:insulin                               -1.707e-02
## pregnant:pressure:triceps:mass                                  -4.642e-02
## pregnant:pressure:insulin:mass                                  -1.640e-02
## pregnant:triceps:insulin:mass                                   -3.551e-02
## pressure:triceps:insulin:mass                                   -1.204e-03
## pregnant:pressure:triceps:pedigree                              -2.533e+00
## pregnant:pressure:insulin:pedigree                              -9.213e-01
## pregnant:triceps:insulin:pedigree                               -1.712e+00
## pressure:triceps:insulin:pedigree                               -4.020e-02
## pregnant:pressure:mass:pedigree                                 -4.173e+00
## pregnant:triceps:mass:pedigree                                  -6.176e+00
## pressure:triceps:mass:pedigree                                  -8.664e-02
## pregnant:insulin:mass:pedigree                                  -2.316e+00
## pressure:insulin:mass:pedigree                                  -8.406e-02
## triceps:insulin:mass:pedigree                                   -9.440e-02
## pregnant:pressure:triceps:age                                   -8.591e-02
## pregnant:pressure:insulin:age                                   -2.930e-02
## pregnant:triceps:insulin:age                                    -6.470e-02
## pressure:triceps:insulin:age                                    -2.759e-03
## pregnant:pressure:mass:age                                      -9.469e-02
## pregnant:triceps:mass:age                                       -1.794e-01
## pressure:triceps:mass:age                                       -7.668e-03
## pregnant:insulin:mass:age                                       -6.293e-02
## pressure:insulin:mass:age                                       -2.904e-03
## triceps:insulin:mass:age                                        -4.934e-03
## pregnant:pressure:pedigree:age                                  -6.815e+00
## pregnant:triceps:pedigree:age                                   -1.080e+01
## pressure:triceps:pedigree:age                                   -2.213e-01
## pregnant:insulin:pedigree:age                                   -4.196e+00
## pressure:insulin:pedigree:age                                   -1.665e-01
## triceps:insulin:pedigree:age                                    -2.446e-01
## pregnant:mass:pedigree:age                                      -1.611e+01
## pressure:mass:pedigree:age                                      -5.473e-01
## triceps:mass:pedigree:age                                       -7.083e-01
## insulin:mass:pedigree:age                                       -3.505e-01
## pregnant:pressure:triceps:diabetespos                           -3.176e+01
## pregnant:pressure:insulin:diabetespos                           -3.195e+00
## pregnant:triceps:insulin:diabetespos                            -5.893e+00
## pressure:triceps:insulin:diabetespos                            -2.466e+00
## pregnant:pressure:mass:diabetespos                              -4.863e+01
## pregnant:triceps:mass:diabetespos                               -9.862e+01
## pressure:triceps:mass:diabetespos                               -7.153e+00
## pregnant:insulin:mass:diabetespos                               -9.853e+00
## pressure:insulin:mass:diabetespos                               -1.855e+00
## triceps:insulin:mass:diabetespos                                -4.997e+00
## pregnant:pressure:pedigree:diabetespos                          -3.190e+03
## pregnant:triceps:pedigree:diabetespos                           -6.288e+03
## pressure:triceps:pedigree:diabetespos                           -5.813e+02
## pregnant:insulin:pedigree:diabetespos                           -6.779e+02
## pressure:insulin:pedigree:diabetespos                           -1.661e+02
## triceps:insulin:pedigree:diabetespos                            -3.950e+02
## pregnant:mass:pedigree:diabetespos                              -9.487e+03
## pressure:mass:pedigree:diabetespos                              -6.253e+02
## triceps:mass:pedigree:diabetespos                               -1.351e+03
## insulin:mass:pedigree:diabetespos                               -3.518e+02
## pregnant:pressure:age:diabetespos                               -7.104e+01
## pregnant:triceps:age:diabetespos                                -1.546e+02
## pressure:triceps:age:diabetespos                                -1.069e+01
## pregnant:insulin:age:diabetespos                                -2.585e+01
## pressure:insulin:age:diabetespos                                -2.985e+00
## triceps:insulin:age:diabetespos                                 -7.592e+00
## pregnant:mass:age:diabetespos                                   -1.895e+02
## pressure:mass:age:diabetespos                                   -1.036e+01
## triceps:mass:age:diabetespos                                    -2.482e+01
## insulin:mass:age:diabetespos                                    -6.489e+00
## pregnant:pedigree:age:diabetespos                               -1.413e+04
## pressure:pedigree:age:diabetespos                               -8.804e+02
## triceps:pedigree:age:diabetespos                                -1.966e+03
## insulin:pedigree:age:diabetespos                                -5.118e+02
## mass:pedigree:age:diabetespos                                   -1.958e+03
## pregnant:pressure:triceps:insulin:mass                           4.308e-04
## pregnant:pressure:triceps:insulin:pedigree                       1.744e-02
## pregnant:pressure:triceps:mass:pedigree                          7.612e-02
## pregnant:pressure:insulin:mass:pedigree                          2.816e-02
## pregnant:triceps:insulin:mass:pedigree                           4.969e-02
## pressure:triceps:insulin:mass:pedigree                           9.466e-04
## pregnant:pressure:triceps:insulin:age                            8.199e-04
## pregnant:pressure:triceps:mass:age                               2.282e-03
## pregnant:pressure:insulin:mass:age                               8.220e-04
## pregnant:triceps:insulin:mass:age                                1.699e-03
## pressure:triceps:insulin:mass:age                                6.939e-05
## pregnant:pressure:triceps:pedigree:age                           1.302e-01
## pregnant:pressure:insulin:pedigree:age                           5.283e-02
## pregnant:triceps:insulin:pedigree:age                            9.741e-02
## pressure:triceps:insulin:pedigree:age                            2.855e-03
## pregnant:pressure:mass:pedigree:age                              2.111e-01
## pregnant:triceps:mass:pedigree:age                               3.250e-01
## pressure:triceps:mass:pedigree:age                               7.121e-03
## pregnant:insulin:mass:pedigree:age                               1.271e-01
## pressure:insulin:mass:pedigree:age                               4.709e-03
## triceps:insulin:mass:pedigree:age                                6.492e-03
## pregnant:pressure:triceps:insulin:diabetespos                    1.027e-01
## pregnant:pressure:triceps:mass:diabetespos                       1.326e+00
## pregnant:pressure:insulin:mass:diabetespos                       1.637e-01
## pregnant:triceps:insulin:mass:diabetespos                        2.266e-01
## pressure:triceps:insulin:mass:diabetespos                        6.267e-02
## pregnant:pressure:triceps:pedigree:diabetespos                   7.525e+01
## pregnant:pressure:insulin:pedigree:diabetespos                   9.397e+00
## pregnant:triceps:insulin:pedigree:diabetespos                    1.291e+01
## pressure:triceps:insulin:pedigree:diabetespos                    5.018e+00
## pregnant:pressure:mass:pedigree:diabetespos                      1.276e+02
## pregnant:triceps:mass:pedigree:diabetespos                       2.234e+02
## pressure:triceps:mass:pedigree:diabetespos                       1.693e+01
## pregnant:insulin:mass:pedigree:diabetespos                       2.850e+01
## pressure:insulin:mass:pedigree:diabetespos                       4.695e+00
## triceps:insulin:mass:pedigree:diabetespos                        1.038e+01
## pregnant:pressure:triceps:age:diabetespos                        2.063e+00
## pregnant:pressure:insulin:age:diabetespos                        3.718e-01
## pregnant:triceps:insulin:age:diabetespos                         7.541e-01
## pressure:triceps:insulin:age:diabetespos                         9.722e-02
## pregnant:pressure:mass:age:diabetespos                           2.584e+00
## pregnant:triceps:mass:age:diabetespos                            5.194e+00
## pressure:triceps:mass:age:diabetespos                            3.027e-01
## pregnant:insulin:mass:age:diabetespos                            8.614e-01
## pressure:insulin:mass:age:diabetespos                            8.136e-02
## triceps:insulin:mass:age:diabetespos                             1.992e-01
## pregnant:pressure:pedigree:age:diabetespos                       1.888e+02
## pregnant:triceps:pedigree:age:diabetespos                        3.824e+02
## pressure:triceps:pedigree:age:diabetespos                        2.430e+01
## pregnant:insulin:pedigree:age:diabetespos                        6.194e+01
## pressure:insulin:pedigree:age:diabetespos                        6.729e+00
## triceps:insulin:pedigree:age:diabetespos                         1.540e+01
## pregnant:mass:pedigree:age:diabetespos                           4.592e+02
## pressure:mass:pedigree:age:diabetespos                           2.603e+01
## triceps:mass:pedigree:age:diabetespos                            5.409e+01
## insulin:mass:pedigree:age:diabetespos                            1.396e+01
## pregnant:pressure:triceps:insulin:mass:pedigree                 -5.231e-04
## pregnant:pressure:triceps:insulin:mass:age                      -2.146e-05
## pregnant:pressure:triceps:insulin:pedigree:age                  -1.121e-03
## pregnant:pressure:triceps:mass:pedigree:age                     -4.027e-03
## pregnant:pressure:insulin:mass:pedigree:age                     -1.601e-03
## pregnant:triceps:insulin:mass:pedigree:age                      -2.860e-03
## pressure:triceps:insulin:mass:pedigree:age                      -7.656e-05
## pregnant:pressure:triceps:insulin:mass:diabetespos              -4.008e-03
## pregnant:pressure:triceps:insulin:pedigree:diabetespos          -1.679e-01
## pregnant:pressure:triceps:mass:pedigree:diabetespos             -2.913e+00
## pregnant:pressure:insulin:mass:pedigree:diabetespos             -4.277e-01
## pregnant:triceps:insulin:mass:pedigree:diabetespos              -5.014e-01
## pressure:triceps:insulin:mass:pedigree:diabetespos              -1.345e-01
## pregnant:pressure:triceps:insulin:age:diabetespos               -1.094e-02
## pregnant:pressure:triceps:mass:age:diabetespos                  -7.055e-02
## pregnant:pressure:insulin:mass:age:diabetespos                  -1.253e-02
## pregnant:triceps:insulin:mass:age:diabetespos                   -2.293e-02
## pressure:triceps:insulin:mass:age:diabetespos                   -2.519e-03
## pregnant:pressure:triceps:pedigree:age:diabetespos              -4.995e+00
## pregnant:pressure:insulin:pedigree:age:diabetespos              -8.663e-01
## pregnant:triceps:insulin:pedigree:age:diabetespos               -1.656e+00
## pressure:triceps:insulin:pedigree:age:diabetespos               -1.972e-01
## pregnant:pressure:mass:pedigree:age:diabetespos                 -6.304e+00
## pregnant:triceps:mass:pedigree:age:diabetespos                  -1.190e+01
## pressure:triceps:mass:pedigree:age:diabetespos                  -6.871e-01
## pregnant:insulin:mass:pedigree:age:diabetespos                  -1.970e+00
## pressure:insulin:mass:pedigree:age:diabetespos                  -1.869e-01
## triceps:insulin:mass:pedigree:age:diabetespos                   -4.027e-01
## pregnant:pressure:triceps:insulin:mass:pedigree:age              3.332e-05
## pregnant:pressure:triceps:insulin:mass:pedigree:diabetespos      7.566e-03
## pregnant:pressure:triceps:insulin:mass:age:diabetespos           3.369e-04
## pregnant:pressure:triceps:insulin:pedigree:age:diabetespos       2.269e-02
## pregnant:pressure:triceps:mass:pedigree:age:diabetespos          1.603e-01
## pregnant:pressure:insulin:mass:pedigree:age:diabetespos          2.840e-02
## pregnant:triceps:insulin:mass:pedigree:age:diabetespos           4.899e-02
## pressure:triceps:insulin:mass:pedigree:age:diabetespos           5.232e-03
## pregnant:pressure:triceps:insulin:mass:pedigree:age:diabetespos -6.963e-04
##                                                                 Std. Error
## (Intercept)                                                      1.234e+04
## pregnant                                                         4.180e+03
## pressure                                                         1.736e+02
## triceps                                                          4.318e+02
## insulin                                                          1.094e+02
## mass                                                             3.911e+02
## pedigree                                                         2.849e+04
## age                                                              5.135e+02
## diabetespos                                                      6.976e+05
## pregnant:pressure                                                5.748e+01
## pregnant:triceps                                                 1.412e+02
## pressure:triceps                                                 6.076e+00
## pregnant:insulin                                                 3.651e+01
## pressure:insulin                                                 1.561e+00
## triceps:insulin                                                  3.874e+00
## pregnant:mass                                                    1.281e+02
## pressure:mass                                                    5.502e+00
## triceps:mass                                                     1.297e+01
## insulin:mass                                                     3.375e+00
## pregnant:pedigree                                                9.255e+03
## pressure:pedigree                                                3.992e+02
## triceps:pedigree                                                 9.698e+02
## insulin:pedigree                                                 2.464e+02
## mass:pedigree                                                    9.133e+02
## pregnant:age                                                     1.658e+02
## pressure:age                                                     7.173e+00
## triceps:age                                                      1.772e+01
## insulin:age                                                      4.732e+00
## mass:age                                                         1.614e+01
## pedigree:age                                                     1.174e+03
## pregnant:diabetespos                                             1.039e+05
## pressure:diabetespos                                             9.907e+03
## triceps:diabetespos                                              2.528e+04
## insulin:diabetespos                                              4.238e+03
## mass:diabetespos                                                 1.852e+04
## pedigree:diabetespos                                             1.261e+06
## age:diabetespos                                                  2.205e+04
## pregnant:pressure:triceps                                        1.910e+00
## pregnant:pressure:insulin                                        4.999e-01
## pregnant:triceps:insulin                                         1.192e+00
## pressure:triceps:insulin                                         5.534e-02
## pregnant:pressure:mass                                           1.751e+00
## pregnant:triceps:mass                                            4.307e+00
## pressure:triceps:mass                                            1.833e-01
## pregnant:insulin:mass                                            1.109e+00
## pressure:insulin:mass                                            4.784e-02
## triceps:insulin:mass                                             1.144e-01
## pregnant:pressure:pedigree                                       1.285e+02
## pregnant:triceps:pedigree                                        3.172e+02
## pressure:triceps:pedigree                                        1.361e+01
## pregnant:insulin:pedigree                                        7.303e+01
## pressure:insulin:pedigree                                        3.458e+00
## triceps:insulin:pedigree                                         8.270e+00
## pregnant:mass:pedigree                                           2.903e+02
## pressure:mass:pedigree                                           1.278e+01
## triceps:mass:pedigree                                            2.894e+01
## insulin:mass:pedigree                                            7.806e+00
## pregnant:pressure:age                                            2.272e+00
## pregnant:triceps:age                                             5.400e+00
## pressure:triceps:age                                             2.482e-01
## pregnant:insulin:age                                             1.484e+00
## pressure:insulin:age                                             6.696e-02
## triceps:insulin:age                                              1.657e-01
## pregnant:mass:age                                                4.954e+00
## pressure:mass:age                                                2.250e-01
## triceps:mass:age                                                 5.242e-01
## insulin:mass:age                                                 1.449e-01
## pregnant:pedigree:age                                            3.560e+02
## pressure:pedigree:age                                            1.641e+01
## triceps:pedigree:age                                             3.975e+01
## insulin:pedigree:age                                             1.057e+01
## mass:pedigree:age                                                3.733e+01
## pregnant:pressure:diabetespos                                    1.453e+03
## pregnant:triceps:diabetespos                                     3.835e+03
## pressure:triceps:diabetespos                                     3.504e+02
## pregnant:insulin:diabetespos                                     5.534e+02
## pressure:insulin:diabetespos                                     6.142e+01
## triceps:insulin:diabetespos                                      1.512e+02
## pregnant:mass:diabetespos                                        2.704e+03
## pressure:mass:diabetespos                                        2.638e+02
## triceps:mass:diabetespos                                         6.687e+02
## insulin:mass:diabetespos                                         1.117e+02
## pregnant:pedigree:diabetespos                                    1.965e+05
## pressure:pedigree:diabetespos                                    1.758e+04
## triceps:pedigree:diabetespos                                     4.534e+04
## insulin:pedigree:diabetespos                                     7.568e+03
## mass:pedigree:diabetespos                                        3.448e+04
## pregnant:age:diabetespos                                         3.048e+03
## pressure:age:diabetespos                                         3.152e+02
## triceps:age:diabetespos                                          8.064e+02
## insulin:age:diabetespos                                          1.349e+02
## mass:age:diabetespos                                             5.955e+02
## pedigree:age:diabetespos                                         4.194e+04
## pregnant:pressure:triceps:insulin                                1.608e-02
## pregnant:pressure:triceps:mass                                   5.807e-02
## pregnant:pressure:insulin:mass                                   1.507e-02
## pregnant:triceps:insulin:mass                                    3.598e-02
## pressure:triceps:insulin:mass                                    1.631e-03
## pregnant:pressure:triceps:pedigree                               4.345e+00
## pregnant:pressure:insulin:pedigree                               1.008e+00
## pregnant:triceps:insulin:pedigree                                2.370e+00
## pressure:triceps:insulin:pedigree                                1.173e-01
## pregnant:pressure:mass:pedigree                                  4.027e+00
## pregnant:triceps:mass:pedigree                                   9.719e+00
## pressure:triceps:mass:pedigree                                   4.063e-01
## pregnant:insulin:mass:pedigree                                   2.256e+00
## pressure:insulin:mass:pedigree                                   1.079e-01
## triceps:insulin:mass:pedigree                                    2.467e-01
## pregnant:pressure:triceps:age                                    7.287e-02
## pregnant:pressure:insulin:age                                    2.017e-02
## pregnant:triceps:insulin:age                                     4.712e-02
## pressure:triceps:insulin:age                                     2.352e-03
## pregnant:pressure:mass:age                                       6.757e-02
## pregnant:triceps:mass:age                                        1.604e-01
## pressure:triceps:mass:age                                        7.362e-03
## pregnant:insulin:mass:age                                        4.455e-02
## pressure:insulin:mass:age                                        2.035e-03
## triceps:insulin:mass:age                                         4.837e-03
## pregnant:pressure:pedigree:age                                   4.904e+00
## pregnant:triceps:pedigree:age                                    1.178e+01
## pressure:triceps:pedigree:age                                    5.574e-01
## pregnant:insulin:pedigree:age                                    2.925e+00
## pressure:insulin:pedigree:age                                    1.481e-01
## triceps:insulin:pedigree:age                                     3.538e-01
## pregnant:mass:pedigree:age                                       1.087e+01
## pressure:mass:pedigree:age                                       5.209e-01
## triceps:mass:pedigree:age                                        1.169e+00
## insulin:mass:pedigree:age                                        3.337e-01
## pregnant:pressure:triceps:diabetespos                            5.189e+01
## pregnant:pressure:insulin:diabetespos                            8.153e+00
## pregnant:triceps:insulin:diabetespos                             2.062e+01
## pressure:triceps:insulin:diabetespos                             2.141e+00
## pregnant:pressure:mass:diabetespos                               3.835e+01
## pregnant:triceps:mass:diabetespos                                9.853e+01
## pressure:triceps:mass:diabetespos                                9.290e+00
## pregnant:insulin:mass:diabetespos                                1.385e+01
## pressure:insulin:mass:diabetespos                                1.626e+00
## triceps:insulin:mass:diabetespos                                 3.965e+00
## pregnant:pressure:pedigree:diabetespos                           2.650e+03
## pregnant:triceps:pedigree:diabetespos                            7.080e+03
## pressure:triceps:pedigree:diabetespos                            6.117e+02
## pregnant:insulin:pedigree:diabetespos                            9.498e+02
## pressure:insulin:pedigree:diabetespos                            1.071e+02
## triceps:insulin:pedigree:diabetespos                             2.664e+02
## pregnant:mass:pedigree:diabetespos                               5.459e+03
## pressure:mass:pedigree:diabetespos                               4.847e+02
## triceps:mass:pedigree:diabetespos                                1.223e+03
## insulin:mass:pedigree:diabetespos                                2.038e+02
## pregnant:pressure:age:diabetespos                                4.388e+01
## pregnant:triceps:age:diabetespos                                 1.141e+02
## pressure:triceps:age:diabetespos                                 1.127e+01
## pregnant:insulin:age:diabetespos                                 1.621e+01
## pressure:insulin:age:diabetespos                                 1.958e+00
## triceps:insulin:age:diabetespos                                  4.835e+00
## pregnant:mass:age:diabetespos                                    8.265e+01
## pressure:mass:age:diabetespos                                    8.520e+00
## triceps:mass:age:diabetespos                                     2.158e+01
## insulin:mass:age:diabetespos                                     3.611e+00
## pregnant:pedigree:age:diabetespos                                6.785e+03
## pressure:pedigree:age:diabetespos                                5.870e+02
## triceps:pedigree:age:diabetespos                                 1.492e+03
## insulin:pedigree:age:diabetespos                                 2.522e+02
## mass:pedigree:age:diabetespos                                    1.157e+03
## pregnant:pressure:triceps:insulin:mass                           4.820e-04
## pregnant:pressure:triceps:insulin:pedigree                       3.245e-02
## pregnant:pressure:triceps:mass:pedigree                          1.333e-01
## pregnant:pressure:insulin:mass:pedigree                          3.082e-02
## pregnant:triceps:insulin:mass:pedigree                           7.151e-02
## pressure:triceps:insulin:mass:pedigree                           3.459e-03
## pregnant:pressure:triceps:insulin:age                            6.317e-04
## pregnant:pressure:triceps:mass:age                               2.157e-03
## pregnant:pressure:insulin:mass:age                               6.024e-04
## pregnant:triceps:insulin:mass:age                                1.402e-03
## pressure:triceps:insulin:mass:age                                6.844e-05
## pregnant:pressure:triceps:pedigree:age                           1.603e-01
## pregnant:pressure:insulin:pedigree:age                           3.993e-02
## pregnant:triceps:insulin:pedigree:age                            9.307e-02
## pressure:triceps:insulin:pedigree:age                            5.004e-03
## pregnant:pressure:mass:pedigree:age                              1.498e-01
## pregnant:triceps:mass:pedigree:age                               3.509e-01
## pressure:triceps:mass:pedigree:age                               1.639e-02
## pregnant:insulin:mass:pedigree:age                               8.930e-02
## pressure:insulin:mass:pedigree:age                               4.608e-03
## triceps:insulin:mass:pedigree:age                                1.048e-02
## pregnant:pressure:triceps:insulin:diabetespos                    2.920e-01
## pregnant:pressure:triceps:mass:diabetespos                       1.345e+00
## pregnant:pressure:insulin:mass:diabetespos                       2.089e-01
## pregnant:triceps:insulin:mass:diabetespos                        5.146e-01
## pressure:triceps:insulin:mass:diabetespos                        5.634e-02
## pregnant:pressure:triceps:pedigree:diabetespos                   9.301e+01
## pregnant:pressure:insulin:pedigree:diabetespos                   1.352e+01
## pregnant:triceps:insulin:pedigree:diabetespos                    3.555e+01
## pressure:triceps:insulin:pedigree:diabetespos                    3.655e+00
## pregnant:pressure:mass:pedigree:diabetespos                      7.490e+01
## pregnant:triceps:mass:pedigree:diabetespos                       1.892e+02
## pressure:triceps:mass:pedigree:diabetespos                       1.661e+01
## pregnant:insulin:mass:pedigree:diabetespos                       2.474e+01
## pressure:insulin:mass:pedigree:diabetespos                       2.915e+00
## triceps:insulin:mass:pedigree:diabetespos                        7.088e+00
## pregnant:pressure:triceps:age:diabetespos                        1.591e+00
## pregnant:pressure:insulin:age:diabetespos                        2.478e-01
## pregnant:triceps:insulin:age:diabetespos                         6.243e-01
## pressure:triceps:insulin:age:diabetespos                         6.881e-02
## pregnant:pressure:mass:age:diabetespos                           1.201e+00
## pregnant:triceps:mass:age:diabetespos                            2.987e+00
## pressure:triceps:mass:age:diabetespos                            3.022e-01
## pregnant:insulin:mass:age:diabetespos                            4.183e-01
## pressure:insulin:mass:age:diabetespos                            5.254e-02
## triceps:insulin:mass:age:diabetespos                             1.283e-01
## pregnant:pressure:pedigree:age:diabetespos                       9.381e+01
## pregnant:triceps:pedigree:age:diabetespos                        2.355e+02
## pressure:triceps:pedigree:age:diabetespos                        2.021e+01
## pregnant:insulin:pedigree:age:diabetespos                        3.232e+01
## pressure:insulin:pedigree:age:diabetespos                        3.568e+00
## triceps:insulin:pedigree:age:diabetespos                         8.792e+00
## pregnant:mass:pedigree:age:diabetespos                           1.928e+02
## pressure:mass:pedigree:age:diabetespos                           1.634e+01
## triceps:mass:pedigree:age:diabetespos                            4.045e+01
## insulin:mass:pedigree:age:diabetespos                            6.855e+00
## pregnant:pressure:triceps:insulin:mass:pedigree                  9.705e-04
## pregnant:pressure:triceps:insulin:mass:age                       1.870e-05
## pregnant:pressure:triceps:insulin:pedigree:age                   1.263e-03
## pregnant:pressure:triceps:mass:pedigree:age                      4.780e-03
## pregnant:pressure:insulin:mass:pedigree:age                      1.211e-03
## pregnant:triceps:insulin:mass:pedigree:age                       2.761e-03
## pressure:triceps:insulin:mass:pedigree:age                       1.467e-04
## pregnant:pressure:triceps:insulin:mass:diabetespos               7.403e-03
## pregnant:pressure:triceps:insulin:pedigree:diabetespos           4.869e-01
## pregnant:pressure:triceps:mass:pedigree:diabetespos              2.519e+00
## pregnant:pressure:insulin:mass:pedigree:diabetespos              3.608e-01
## pregnant:triceps:insulin:mass:pedigree:diabetespos               9.077e-01
## pressure:triceps:insulin:mass:pedigree:diabetespos               9.810e-02
## pregnant:pressure:triceps:insulin:age:diabetespos                9.135e-03
## pregnant:pressure:triceps:mass:age:diabetespos                   4.209e-02
## pregnant:pressure:insulin:mass:age:diabetespos                   6.530e-03
## pregnant:triceps:insulin:mass:age:diabetespos                    1.581e-02
## pressure:triceps:insulin:mass:age:diabetespos                    1.831e-03
## pregnant:pressure:triceps:pedigree:age:diabetespos               3.178e+00
## pregnant:pressure:insulin:pedigree:age:diabetespos               4.723e-01
## pregnant:triceps:insulin:pedigree:age:diabetespos                1.186e+00
## pressure:triceps:insulin:pedigree:age:diabetespos                1.208e-01
## pregnant:pressure:mass:pedigree:age:diabetespos                  2.708e+00
## pregnant:triceps:mass:pedigree:age:diabetespos                   6.381e+00
## pressure:triceps:mass:pedigree:age:diabetespos                   5.521e-01
## pregnant:insulin:mass:pedigree:age:diabetespos                   8.744e-01
## pressure:insulin:mass:pedigree:age:diabetespos                   9.803e-02
## triceps:insulin:mass:pedigree:age:diabetespos                    2.352e-01
## pregnant:pressure:triceps:insulin:mass:pedigree:age              3.721e-05
## pregnant:pressure:triceps:insulin:mass:pedigree:diabetespos      1.265e-02
## pregnant:pressure:triceps:insulin:mass:age:diabetespos           2.354e-04
## pregnant:pressure:triceps:insulin:pedigree:age:diabetespos       1.669e-02
## pregnant:pressure:triceps:mass:pedigree:age:diabetespos          8.738e-02
## pregnant:pressure:insulin:mass:pedigree:age:diabetespos          1.306e-02
## pregnant:triceps:insulin:mass:pedigree:age:diabetespos           3.082e-02
## pressure:triceps:insulin:mass:pedigree:age:diabetespos           3.262e-03
## pregnant:pressure:triceps:insulin:mass:pedigree:age:diabetespos  4.424e-04
##                                                                 t value
## (Intercept)                                                      -1.466
## pregnant                                                          1.252
## pressure                                                          1.384
## triceps                                                           1.067
## insulin                                                           1.315
## mass                                                              1.265
## pedigree                                                          1.010
## age                                                               1.737
## diabetespos                                                       0.875
## pregnant:pressure                                                -1.186
## pregnant:triceps                                                 -1.037
## pressure:triceps                                                 -0.908
## pregnant:insulin                                                 -1.288
## pressure:insulin                                                 -1.341
## triceps:insulin                                                  -0.987
## pregnant:mass                                                    -1.125
## pressure:mass                                                    -1.213
## triceps:mass                                                     -0.834
## insulin:mass                                                     -1.126
## pregnant:pedigree                                                -1.138
## pressure:pedigree                                                -0.863
## triceps:pedigree                                                 -0.421
## insulin:pedigree                                                 -0.938
## mass:pedigree                                                    -0.918
## pregnant:age                                                     -1.518
## pressure:age                                                     -1.666
## triceps:age                                                      -1.340
## insulin:age                                                      -1.519
## mass:age                                                         -1.559
## pedigree:age                                                     -1.235
## pregnant:diabetespos                                             -0.770
## pressure:diabetespos                                             -0.713
## triceps:diabetespos                                              -0.842
## insulin:diabetespos                                              -1.313
## mass:diabetespos                                                 -1.009
## pedigree:diabetespos                                             -1.274
## age:diabetespos                                                  -1.275
## pregnant:pressure:triceps                                         0.965
## pregnant:pressure:insulin                                         1.194
## pregnant:triceps:insulin                                          1.173
## pressure:triceps:insulin                                          0.938
## pregnant:pressure:mass                                            1.077
## pregnant:triceps:mass                                             0.854
## pressure:triceps:mass                                             0.723
## pregnant:insulin:mass                                             1.167
## pressure:insulin:mass                                             1.164
## triceps:insulin:mass                                              0.761
## pregnant:pressure:pedigree                                        1.060
## pregnant:triceps:pedigree                                         0.672
## pressure:triceps:pedigree                                         0.216
## pregnant:insulin:pedigree                                         1.054
## pressure:insulin:pedigree                                         0.881
## triceps:insulin:pedigree                                          0.480
## pregnant:mass:pedigree                                            1.092
## pressure:mass:pedigree                                            0.807
## triceps:mass:pedigree                                             0.370
## insulin:mass:pedigree                                             0.822
## pregnant:pressure:age                                             1.456
## pregnant:triceps:age                                              1.256
## pressure:triceps:age                                              1.177
## pregnant:insulin:age                                              1.506
## pressure:insulin:age                                              1.581
## triceps:insulin:age                                               1.202
## pregnant:mass:age                                                 1.450
## pressure:mass:age                                                 1.524
## triceps:mass:age                                                  1.159
## insulin:mass:age                                                  1.357
## pregnant:pedigree:age                                             1.474
## pressure:pedigree:age                                             1.091
## triceps:pedigree:age                                              0.612
## insulin:pedigree:age                                              1.161
## mass:pedigree:age                                                 1.165
## pregnant:pressure:diabetespos                                     0.694
## pregnant:triceps:diabetespos                                      0.656
## pressure:triceps:diabetespos                                      0.724
## pregnant:insulin:diabetespos                                      0.339
## pressure:insulin:diabetespos                                      1.120
## triceps:insulin:diabetespos                                       1.283
## pregnant:mass:diabetespos                                         1.328
## pressure:mass:diabetespos                                         0.832
## triceps:mass:diabetespos                                          0.899
## insulin:mass:diabetespos                                          1.355
## pregnant:pedigree:diabetespos                                     1.290
## pressure:pedigree:diabetespos                                     1.153
## triceps:pedigree:diabetespos                                      1.064
## insulin:pedigree:diabetespos                                      1.685
## mass:pedigree:diabetespos                                         1.380
## pregnant:age:diabetespos                                          1.743
## pressure:age:diabetespos                                          1.090
## triceps:age:diabetespos                                           1.081
## insulin:age:diabetespos                                           1.751
## mass:age:diabetespos                                              1.419
## pedigree:age:diabetespos                                          1.623
## pregnant:pressure:triceps:insulin                                -1.062
## pregnant:pressure:triceps:mass                                   -0.799
## pregnant:pressure:insulin:mass                                   -1.088
## pregnant:triceps:insulin:mass                                    -0.987
## pressure:triceps:insulin:mass                                    -0.738
## pregnant:pressure:triceps:pedigree                               -0.583
## pregnant:pressure:insulin:pedigree                               -0.914
## pregnant:triceps:insulin:pedigree                                -0.722
## pressure:triceps:insulin:pedigree                                -0.343
## pregnant:pressure:mass:pedigree                                  -1.036
## pregnant:triceps:mass:pedigree                                   -0.635
## pressure:triceps:mass:pedigree                                   -0.213
## pregnant:insulin:mass:pedigree                                   -1.027
## pressure:insulin:mass:pedigree                                   -0.779
## triceps:insulin:mass:pedigree                                    -0.383
## pregnant:pressure:triceps:age                                    -1.179
## pregnant:pressure:insulin:age                                    -1.453
## pregnant:triceps:insulin:age                                     -1.373
## pressure:triceps:insulin:age                                     -1.173
## pregnant:pressure:mass:age                                       -1.401
## pregnant:triceps:mass:age                                        -1.119
## pressure:triceps:mass:age                                        -1.042
## pregnant:insulin:mass:age                                        -1.412
## pressure:insulin:mass:age                                        -1.427
## triceps:insulin:mass:age                                         -1.020
## pregnant:pressure:pedigree:age                                   -1.390
## pregnant:triceps:pedigree:age                                    -0.917
## pressure:triceps:pedigree:age                                    -0.397
## pregnant:insulin:pedigree:age                                    -1.434
## pressure:insulin:pedigree:age                                    -1.124
## triceps:insulin:pedigree:age                                     -0.691
## pregnant:mass:pedigree:age                                       -1.482
## pressure:mass:pedigree:age                                       -1.051
## triceps:mass:pedigree:age                                        -0.606
## insulin:mass:pedigree:age                                        -1.050
## pregnant:pressure:triceps:diabetespos                            -0.612
## pregnant:pressure:insulin:diabetespos                            -0.392
## pregnant:triceps:insulin:diabetespos                             -0.286
## pressure:triceps:insulin:diabetespos                             -1.152
## pregnant:pressure:mass:diabetespos                               -1.268
## pregnant:triceps:mass:diabetespos                                -1.001
## pressure:triceps:mass:diabetespos                                -0.770
## pregnant:insulin:mass:diabetespos                                -0.712
## pressure:insulin:mass:diabetespos                                -1.140
## triceps:insulin:mass:diabetespos                                 -1.260
## pregnant:pressure:pedigree:diabetespos                           -1.204
## pregnant:triceps:pedigree:diabetespos                            -0.888
## pressure:triceps:pedigree:diabetespos                            -0.950
## pregnant:insulin:pedigree:diabetespos                            -0.714
## pressure:insulin:pedigree:diabetespos                            -1.551
## triceps:insulin:pedigree:diabetespos                             -1.483
## pregnant:mass:pedigree:diabetespos                               -1.738
## pressure:mass:pedigree:diabetespos                               -1.290
## triceps:mass:pedigree:diabetespos                                -1.105
## insulin:mass:pedigree:diabetespos                                -1.726
## pregnant:pressure:age:diabetespos                                -1.619
## pregnant:triceps:age:diabetespos                                 -1.355
## pressure:triceps:age:diabetespos                                 -0.948
## pregnant:insulin:age:diabetespos                                 -1.595
## pressure:insulin:age:diabetespos                                 -1.524
## triceps:insulin:age:diabetespos                                  -1.570
## pregnant:mass:age:diabetespos                                    -2.293
## pressure:mass:age:diabetespos                                    -1.216
## triceps:mass:age:diabetespos                                     -1.150
## insulin:mass:age:diabetespos                                     -1.797
## pregnant:pedigree:age:diabetespos                                -2.082
## pressure:pedigree:age:diabetespos                                -1.500
## triceps:pedigree:age:diabetespos                                 -1.317
## insulin:pedigree:age:diabetespos                                 -2.030
## mass:pedigree:age:diabetespos                                    -1.693
## pregnant:pressure:triceps:insulin:mass                            0.894
## pregnant:pressure:triceps:insulin:pedigree                        0.537
## pregnant:pressure:triceps:mass:pedigree                           0.571
## pregnant:pressure:insulin:mass:pedigree                           0.914
## pregnant:triceps:insulin:mass:pedigree                            0.695
## pressure:triceps:insulin:mass:pedigree                            0.274
## pregnant:pressure:triceps:insulin:age                             1.298
## pregnant:pressure:triceps:mass:age                                1.058
## pregnant:pressure:insulin:mass:age                                1.364
## pregnant:triceps:insulin:mass:age                                 1.212
## pressure:triceps:insulin:mass:age                                 1.014
## pregnant:pressure:triceps:pedigree:age                            0.812
## pregnant:pressure:insulin:pedigree:age                            1.323
## pregnant:triceps:insulin:pedigree:age                             1.047
## pressure:triceps:insulin:pedigree:age                             0.571
## pregnant:pressure:mass:pedigree:age                               1.410
## pregnant:triceps:mass:pedigree:age                                0.926
## pressure:triceps:mass:pedigree:age                                0.435
## pregnant:insulin:mass:pedigree:age                                1.423
## pressure:insulin:mass:pedigree:age                                1.022
## triceps:insulin:mass:pedigree:age                                 0.620
## pregnant:pressure:triceps:insulin:diabetespos                     0.352
## pregnant:pressure:triceps:mass:diabetespos                        0.985
## pregnant:pressure:insulin:mass:diabetespos                        0.784
## pregnant:triceps:insulin:mass:diabetespos                         0.440
## pressure:triceps:insulin:mass:diabetespos                         1.112
## pregnant:pressure:triceps:pedigree:diabetespos                    0.809
## pregnant:pressure:insulin:pedigree:diabetespos                    0.695
## pregnant:triceps:insulin:pedigree:diabetespos                     0.363
## pressure:triceps:insulin:pedigree:diabetespos                     1.373
## pregnant:pressure:mass:pedigree:diabetespos                       1.703
## pregnant:triceps:mass:pedigree:diabetespos                        1.181
## pressure:triceps:mass:pedigree:diabetespos                        1.019
## pregnant:insulin:mass:pedigree:diabetespos                        1.152
## pressure:insulin:mass:pedigree:diabetespos                        1.611
## triceps:insulin:mass:pedigree:diabetespos                         1.464
## pregnant:pressure:triceps:age:diabetespos                         1.297
## pregnant:pressure:insulin:age:diabetespos                         1.500
## pregnant:triceps:insulin:age:diabetespos                          1.208
## pressure:triceps:insulin:age:diabetespos                          1.413
## pregnant:pressure:mass:age:diabetespos                            2.152
## pregnant:triceps:mass:age:diabetespos                             1.739
## pressure:triceps:mass:age:diabetespos                             1.002
## pregnant:insulin:mass:age:diabetespos                             2.059
## pressure:insulin:mass:age:diabetespos                             1.548
## triceps:insulin:mass:age:diabetespos                              1.552
## pregnant:pressure:pedigree:age:diabetespos                        2.012
## pregnant:triceps:pedigree:age:diabetespos                         1.623
## pressure:triceps:pedigree:age:diabetespos                         1.202
## pregnant:insulin:pedigree:age:diabetespos                         1.916
## pressure:insulin:pedigree:age:diabetespos                         1.886
## triceps:insulin:pedigree:age:diabetespos                          1.752
## pregnant:mass:pedigree:age:diabetespos                            2.381
## pressure:mass:pedigree:age:diabetespos                            1.593
## triceps:mass:pedigree:age:diabetespos                             1.337
## insulin:mass:pedigree:age:diabetespos                             2.037
## pregnant:pressure:triceps:insulin:mass:pedigree                  -0.539
## pregnant:pressure:triceps:insulin:mass:age                       -1.147
## pregnant:pressure:triceps:insulin:pedigree:age                   -0.887
## pregnant:pressure:triceps:mass:pedigree:age                      -0.842
## pregnant:pressure:insulin:mass:pedigree:age                      -1.322
## pregnant:triceps:insulin:mass:pedigree:age                       -1.036
## pressure:triceps:insulin:mass:pedigree:age                       -0.522
## pregnant:pressure:triceps:insulin:mass:diabetespos               -0.541
## pregnant:pressure:triceps:insulin:pedigree:diabetespos           -0.345
## pregnant:pressure:triceps:mass:pedigree:diabetespos              -1.157
## pregnant:pressure:insulin:mass:pedigree:diabetespos              -1.185
## pregnant:triceps:insulin:mass:pedigree:diabetespos               -0.552
## pressure:triceps:insulin:mass:pedigree:diabetespos               -1.371
## pregnant:pressure:triceps:insulin:age:diabetespos                -1.198
## pregnant:pressure:triceps:mass:age:diabetespos                   -1.676
## pregnant:pressure:insulin:mass:age:diabetespos                   -1.919
## pregnant:triceps:insulin:mass:age:diabetespos                    -1.451
## pressure:triceps:insulin:mass:age:diabetespos                    -1.376
## pregnant:pressure:triceps:pedigree:age:diabetespos               -1.572
## pregnant:pressure:insulin:pedigree:age:diabetespos               -1.834
## pregnant:triceps:insulin:pedigree:age:diabetespos                -1.396
## pressure:triceps:insulin:pedigree:age:diabetespos                -1.632
## pregnant:pressure:mass:pedigree:age:diabetespos                  -2.328
## pregnant:triceps:mass:pedigree:age:diabetespos                   -1.864
## pressure:triceps:mass:pedigree:age:diabetespos                   -1.244
## pregnant:insulin:mass:pedigree:age:diabetespos                   -2.253
## pressure:insulin:mass:pedigree:age:diabetespos                   -1.907
## triceps:insulin:mass:pedigree:age:diabetespos                    -1.712
## pregnant:pressure:triceps:insulin:mass:pedigree:age               0.895
## pregnant:pressure:triceps:insulin:mass:pedigree:diabetespos       0.598
## pregnant:pressure:triceps:insulin:mass:age:diabetespos            1.431
## pregnant:pressure:triceps:insulin:pedigree:age:diabetespos        1.359
## pregnant:pressure:triceps:mass:pedigree:age:diabetespos           1.835
## pregnant:pressure:insulin:mass:pedigree:age:diabetespos           2.174
## pregnant:triceps:insulin:mass:pedigree:age:diabetespos            1.590
## pressure:triceps:insulin:mass:pedigree:age:diabetespos            1.604
## pregnant:pressure:triceps:insulin:mass:pedigree:age:diabetespos  -1.574
##                                                                 Pr(>|t|)  
## (Intercept)                                                       0.1450  
## pregnant                                                          0.2127  
## pressure                                                          0.1686  
## triceps                                                           0.2878  
## insulin                                                           0.1907  
## mass                                                              0.2081  
## pedigree                                                          0.3145  
## age                                                               0.0846 .
## diabetespos                                                       0.3830  
## pregnant:pressure                                                 0.2378  
## pregnant:triceps                                                  0.3016  
## pressure:triceps                                                  0.3655  
## pregnant:insulin                                                  0.1998  
## pressure:insulin                                                  0.1822  
## triceps:insulin                                                   0.3253  
## pregnant:mass                                                     0.2627  
## pressure:mass                                                     0.2271  
## triceps:mass                                                      0.4055  
## insulin:mass                                                      0.2622  
## pregnant:pedigree                                                 0.2571  
## pressure:pedigree                                                 0.3894  
## triceps:pedigree                                                  0.6746  
## insulin:pedigree                                                  0.3499  
## mass:pedigree                                                     0.3601  
## pregnant:age                                                      0.1313  
## pressure:age                                                      0.0979 .
## triceps:age                                                       0.1826  
## insulin:age                                                       0.1311  
## mass:age                                                          0.1213  
## pedigree:age                                                      0.2189  
## pregnant:diabetespos                                              0.4429  
## pressure:diabetespos                                              0.4772  
## triceps:diabetespos                                               0.4011  
## insulin:diabetespos                                               0.1914  
## mass:diabetespos                                                  0.3147  
## pedigree:diabetespos                                              0.2050  
## age:diabetespos                                                   0.2044  
## pregnant:pressure:triceps                                         0.3362  
## pregnant:pressure:insulin                                         0.2346  
## pregnant:triceps:insulin                                          0.2430  
## pressure:triceps:insulin                                          0.3500  
## pregnant:pressure:mass                                            0.2836  
## pregnant:triceps:mass                                             0.3946  
## pressure:triceps:mass                                             0.4709  
## pregnant:insulin:mass                                             0.2453  
## pressure:insulin:mass                                             0.2464  
## triceps:insulin:mass                                              0.4481  
## pregnant:pressure:pedigree                                        0.2910  
## pregnant:triceps:pedigree                                         0.5025  
## pressure:triceps:pedigree                                         0.8293  
## pregnant:insulin:pedigree                                         0.2938  
## pressure:insulin:pedigree                                         0.3799  
## triceps:insulin:pedigree                                          0.6317  
## pregnant:mass:pedigree                                            0.2769  
## pressure:mass:pedigree                                            0.4212  
## triceps:mass:pedigree                                             0.7119  
## insulin:mass:pedigree                                             0.4123  
## pregnant:pressure:age                                             0.1477  
## pregnant:triceps:age                                              0.2112  
## pressure:triceps:age                                              0.2413  
## pregnant:insulin:age                                              0.1344  
## pressure:insulin:age                                              0.1161  
## triceps:insulin:age                                               0.2315  
## pregnant:mass:age                                                 0.1493  
## pressure:mass:age                                                 0.1298  
## triceps:mass:age                                                  0.2483  
## insulin:mass:age                                                  0.1771  
## pregnant:pedigree:age                                             0.1428  
## pressure:pedigree:age                                             0.2770  
## triceps:pedigree:age                                              0.5419  
## insulin:pedigree:age                                              0.2478  
## mass:pedigree:age                                                 0.2461  
## pregnant:pressure:diabetespos                                     0.4889  
## pregnant:triceps:diabetespos                                      0.5129  
## pressure:triceps:diabetespos                                      0.4704  
## pregnant:insulin:diabetespos                                      0.7351  
## pressure:insulin:diabetespos                                      0.2646  
## triceps:insulin:diabetespos                                       0.2018  
## pregnant:mass:diabetespos                                         0.1863  
## pressure:mass:diabetespos                                         0.4070  
## triceps:mass:diabetespos                                          0.3703  
## insulin:mass:diabetespos                                          0.1777  
## pregnant:pedigree:diabetespos                                     0.1993  
## pressure:pedigree:diabetespos                                     0.2511  
## triceps:pedigree:diabetespos                                      0.2894  
## insulin:pedigree:diabetespos                                      0.0943 .
## mass:pedigree:diabetespos                                         0.1698  
## pregnant:age:diabetespos                                          0.0836 .
## pressure:age:diabetespos                                          0.2775  
## triceps:age:diabetespos                                           0.2815  
## insulin:age:diabetespos                                           0.0822 .
## mass:age:diabetespos                                              0.1580  
## pedigree:age:diabetespos                                          0.1068  
## pregnant:pressure:triceps:insulin                                 0.2901  
## pregnant:pressure:triceps:mass                                    0.4255  
## pregnant:pressure:insulin:mass                                    0.2784  
## pregnant:triceps:insulin:mass                                     0.3253  
## pressure:triceps:insulin:mass                                     0.4617  
## pregnant:pressure:triceps:pedigree                                0.5609  
## pregnant:pressure:insulin:pedigree                                0.3623  
## pregnant:triceps:insulin:pedigree                                 0.4712  
## pressure:triceps:insulin:pedigree                                 0.7323  
## pregnant:pressure:mass:pedigree                                   0.3018  
## pregnant:triceps:mass:pedigree                                    0.5262  
## pressure:triceps:mass:pedigree                                    0.8314  
## pregnant:insulin:mass:pedigree                                    0.3063  
## pressure:insulin:mass:pedigree                                    0.4371  
## triceps:insulin:mass:pedigree                                     0.7026  
## pregnant:pressure:triceps:age                                     0.2405  
## pregnant:pressure:insulin:age                                     0.1486  
## pregnant:triceps:insulin:age                                      0.1719  
## pressure:triceps:insulin:age                                      0.2428  
## pregnant:pressure:mass:age                                        0.1634  
## pregnant:triceps:mass:age                                         0.2652  
## pressure:triceps:mass:age                                         0.2994  
## pregnant:insulin:mass:age                                         0.1601  
## pressure:insulin:mass:age                                         0.1559  
## triceps:insulin:mass:age                                          0.3096  
## pregnant:pressure:pedigree:age                                    0.1669  
## pregnant:triceps:pedigree:age                                     0.3610  
## pressure:triceps:pedigree:age                                     0.6920  
## pregnant:insulin:pedigree:age                                     0.1538  
## pressure:insulin:pedigree:age                                     0.2628  
## triceps:insulin:pedigree:age                                      0.4905  
## pregnant:mass:pedigree:age                                        0.1407  
## pressure:mass:pedigree:age                                        0.2953  
## triceps:mass:pedigree:age                                         0.5457  
## insulin:mass:pedigree:age                                         0.2954  
## pregnant:pressure:triceps:diabetespos                             0.5415  
## pregnant:pressure:insulin:diabetespos                             0.6957  
## pregnant:triceps:insulin:diabetespos                              0.7755  
## pressure:triceps:insulin:diabetespos                              0.2514  
## pregnant:pressure:mass:diabetespos                                0.2069  
## pregnant:triceps:mass:diabetespos                                 0.3187  
## pressure:triceps:mass:diabetespos                                 0.4427  
## pregnant:insulin:mass:diabetespos                                 0.4780  
## pressure:insulin:mass:diabetespos                                 0.2562  
## triceps:insulin:mass:diabetespos                                  0.2098  
## pregnant:pressure:pedigree:diabetespos                            0.2307  
## pregnant:triceps:pedigree:diabetespos                             0.3761  
## pressure:triceps:pedigree:diabetespos                             0.3437  
## pregnant:insulin:pedigree:diabetespos                             0.4766  
## pressure:insulin:pedigree:diabetespos                             0.1232  
## triceps:insulin:pedigree:diabetespos                              0.1405  
## pregnant:mass:pedigree:diabetespos                                0.0845 .
## pressure:mass:pedigree:diabetespos                                0.1992  
## triceps:mass:pedigree:diabetespos                                 0.2713  
## insulin:mass:pedigree:diabetespos                                 0.0867 .
## pregnant:pressure:age:diabetespos                                 0.1077  
## pregnant:triceps:age:diabetespos                                  0.1775  
## pressure:triceps:age:diabetespos                                  0.3446  
## pregnant:insulin:age:diabetespos                                  0.1131  
## pressure:insulin:age:diabetespos                                  0.1297  
## triceps:insulin:age:diabetespos                                   0.1187  
## pregnant:mass:age:diabetespos                                     0.0234 *
## pressure:mass:age:diabetespos                                     0.2262  
## triceps:mass:age:diabetespos                                      0.2521  
## insulin:mass:age:diabetespos                                      0.0745 .
## pregnant:pedigree:age:diabetespos                                 0.0392 *
## pressure:pedigree:age:diabetespos                                 0.1360  
## triceps:pedigree:age:diabetespos                                  0.1899  
## insulin:pedigree:age:diabetespos                                  0.0443 *
## mass:pedigree:age:diabetespos                                     0.0928 .
## pregnant:pressure:triceps:insulin:mass                            0.3730  
## pregnant:pressure:triceps:insulin:pedigree                        0.5919  
## pregnant:pressure:triceps:mass:pedigree                           0.5689  
## pregnant:pressure:insulin:mass:pedigree                           0.3625  
## pregnant:triceps:insulin:mass:pedigree                            0.4883  
## pressure:triceps:insulin:mass:pedigree                            0.7848  
## pregnant:pressure:triceps:insulin:age                             0.1965  
## pregnant:pressure:triceps:mass:age                                0.2919  
## pregnant:pressure:insulin:mass:age                                0.1747  
## pregnant:triceps:insulin:mass:age                                 0.2275  
## pressure:triceps:insulin:mass:age                                 0.3124  
## pregnant:pressure:triceps:pedigree:age                            0.4182  
## pregnant:pressure:insulin:pedigree:age                            0.1880  
## pregnant:triceps:insulin:pedigree:age                             0.2971  
## pressure:triceps:insulin:pedigree:age                             0.5692  
## pregnant:pressure:mass:pedigree:age                               0.1609  
## pregnant:triceps:mass:pedigree:age                                0.3561  
## pressure:triceps:mass:pedigree:age                                0.6646  
## pregnant:insulin:mass:pedigree:age                                0.1570  
## pressure:insulin:mass:pedigree:age                                0.3086  
## triceps:insulin:mass:pedigree:age                                 0.5366  
## pregnant:pressure:triceps:insulin:diabetespos                     0.7254  
## pregnant:pressure:triceps:mass:diabetespos                        0.3262  
## pregnant:pressure:insulin:mass:diabetespos                        0.4347  
## pregnant:triceps:insulin:mass:diabetespos                         0.6604  
## pressure:triceps:insulin:mass:diabetespos                         0.2680  
## pregnant:pressure:triceps:pedigree:diabetespos                    0.4199  
## pregnant:pressure:insulin:pedigree:diabetespos                    0.4883  
## pregnant:triceps:insulin:pedigree:diabetespos                     0.7171  
## pressure:triceps:insulin:pedigree:diabetespos                     0.1721  
## pregnant:pressure:mass:pedigree:diabetespos                       0.0908 .
## pregnant:triceps:mass:pedigree:diabetespos                        0.2398  
## pressure:triceps:mass:pedigree:diabetespos                        0.3101  
## pregnant:insulin:mass:pedigree:diabetespos                        0.2513  
## pressure:insulin:mass:pedigree:diabetespos                        0.1095  
## triceps:insulin:mass:pedigree:diabetespos                         0.1454  
## pregnant:pressure:triceps:age:diabetespos                         0.1970  
## pregnant:pressure:insulin:age:diabetespos                         0.1359  
## pregnant:triceps:insulin:age:diabetespos                          0.2292  
## pressure:triceps:insulin:age:diabetespos                          0.1600  
## pregnant:pressure:mass:age:diabetespos                            0.0331 *
## pregnant:triceps:mass:age:diabetespos                             0.0844 .
## pressure:triceps:mass:age:diabetespos                             0.3183  
## pregnant:insulin:mass:age:diabetespos                             0.0414 *
## pressure:insulin:mass:age:diabetespos                             0.1238  
## triceps:insulin:mass:age:diabetespos                              0.1229  
## pregnant:pressure:pedigree:age:diabetespos                        0.0462 *
## pregnant:triceps:pedigree:age:diabetespos                         0.1068  
## pressure:triceps:pedigree:age:diabetespos                         0.2313  
## pregnant:insulin:pedigree:age:diabetespos                         0.0574 .
## pressure:insulin:pedigree:age:diabetespos                         0.0614 .
## triceps:insulin:pedigree:age:diabetespos                          0.0820 .
## pregnant:mass:pedigree:age:diabetespos                            0.0187 *
## pressure:mass:pedigree:age:diabetespos                            0.1134  
## triceps:mass:pedigree:age:diabetespos                             0.1834  
## insulin:mass:pedigree:age:diabetespos                             0.0436 *
## pregnant:pressure:triceps:insulin:mass:pedigree                   0.5908  
## pregnant:pressure:triceps:insulin:mass:age                        0.2532  
## pregnant:pressure:triceps:insulin:pedigree:age                    0.3764  
## pregnant:pressure:triceps:mass:pedigree:age                       0.4010  
## pregnant:pressure:insulin:mass:pedigree:age                       0.1885  
## pregnant:triceps:insulin:mass:pedigree:age                        0.3022  
## pressure:triceps:insulin:mass:pedigree:age                        0.6025  
## pregnant:pressure:triceps:insulin:mass:diabetespos                0.5891  
## pregnant:pressure:triceps:insulin:pedigree:diabetespos            0.7307  
## pregnant:pressure:triceps:mass:pedigree:diabetespos               0.2495  
## pregnant:pressure:insulin:mass:pedigree:diabetespos               0.2379  
## pregnant:triceps:insulin:mass:pedigree:diabetespos                0.5816  
## pressure:triceps:insulin:mass:pedigree:diabetespos                0.1727  
## pregnant:pressure:triceps:insulin:age:diabetespos                 0.2331  
## pregnant:pressure:triceps:mass:age:diabetespos                    0.0960 .
## pregnant:pressure:insulin:mass:age:diabetespos                    0.0571 .
## pregnant:triceps:insulin:mass:age:diabetespos                     0.1492  
## pressure:triceps:insulin:mass:age:diabetespos                     0.1711  
## pregnant:pressure:triceps:pedigree:age:diabetespos                0.1183  
## pregnant:pressure:insulin:pedigree:age:diabetespos                0.0688 .
## pregnant:triceps:insulin:pedigree:age:diabetespos                 0.1650  
## pressure:triceps:insulin:pedigree:age:diabetespos                 0.1050  
## pregnant:pressure:mass:pedigree:age:diabetespos                   0.0214 *
## pregnant:triceps:mass:pedigree:age:diabetespos                    0.0644 .
## pressure:triceps:mass:pedigree:age:diabetespos                    0.2155  
## pregnant:insulin:mass:pedigree:age:diabetespos                    0.0259 *
## pressure:insulin:mass:pedigree:age:diabetespos                    0.0586 .
## triceps:insulin:mass:pedigree:age:diabetespos                     0.0891 .
## pregnant:pressure:triceps:insulin:mass:pedigree:age               0.3722  
## pregnant:pressure:triceps:insulin:mass:pedigree:diabetespos       0.5507  
## pregnant:pressure:triceps:insulin:mass:age:diabetespos            0.1546  
## pregnant:pressure:triceps:insulin:pedigree:age:diabetespos        0.1764  
## pregnant:pressure:triceps:mass:pedigree:age:diabetespos           0.0687 .
## pregnant:pressure:insulin:mass:pedigree:age:diabetespos           0.0314 *
## pregnant:triceps:insulin:mass:pedigree:age:diabetespos            0.1142  
## pressure:triceps:insulin:mass:pedigree:age:diabetespos            0.1110  
## pregnant:pressure:triceps:insulin:mass:pedigree:age:diabetespos   0.1179  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 16.68 on 136 degrees of freedom
##   (376 osservazioni eliminate a causa di valori mancanti)
## Multiple R-squared:  0.8984, Adjusted R-squared:  0.7078 
## F-statistic: 4.715 on 255 and 136 DF,  p-value: < 2.2e-16

Come si può osservare il modello non è interpretabile ma garantisceun buon \(R^2_{adj}\). Eseguendo un modello senza interazioni si otterebbe un \(R^2_{adj}\) del 47% contro il 70% di quello con interazioni. Anche seguendo il criterio dell’informazione di Akaike scegliamo il modello con interazioni. Interessante anche notare come la differenza tra \(R^2_{adj}\) e \(R^2\) nel modello con interazioni, in quanto contiene molti più parametri confronto il modello con interazioni, dove la differenza è nettamente minore.

modGluSemplice = lm(as.formula(paste(varDip, " ~ ",paste(colonne,collapse = " + "))), df)
data.frame(R2 = c(summary(modGlu)$r.squared, summary(modGluSemplice)$r.squared),
           R2adj = c(summary(modGlu)$adj.r.squared, summary(modGluSemplice)$adj.r.squared),
           AIC = c(AIC(modGlu), AIC(modGluSemplice)),
           row.names = c("Con interazioni", "Senza interazioni"))

Nel modello conviene non includere le variabili le quali hanno degli NA sia nella suddetta variabile, sia nella variabile risposta. Un’altra opzione è quella di costruire modelli ad hoc in base alle informazioni disponibili sull’osservazione con NA nella variabile risposta.

righeNA = is.na(df$glucose)
df[righeNA,]
colonne = names(df)[!sapply(1:ncol(df), function(c) sum(is.na(df[,varDip]) & is.na(df[,c]))>0)]
# seleziona le righe con almeno un NA oltre la variabile dipendente e su di esse applica un modello senza le colonne le quali contengono NA nella stessa osservazione con NA sulla variabile dipendente
righe = sapply(1:nrow(df), function(r) sum(sapply(1:ncol(df), function(c) is.na(df[,varDip]) & is.na(df[,c]))[r,]))>1 
df[righe,varDip] = predict(lm(as.formula(paste(varDip, " ~ ",paste(colonne,collapse = " + "))), df),
                     newdata = df[righe,])

# modello completo
righe = sapply(1:nrow(df), function(r) sum(sapply(1:ncol(df), function(c) is.na(df[,varDip]) & is.na(df[,c]))[r,])) == 1
df[righe,varDip] = predict(modGlu, newdata = df[righe,])
df[righeNA,]

Mass

Ora ripeto la procedura con la variabile Mass.

## Start:  AIC=1248.26
## mass ~ pregnant * glucose * pressure * triceps * insulin * pedigree * 
##     age * diabetes
## 
##                                                                   Df Sum of Sq
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age:diabetes  1    12.052
## <none>                                                                        
##                                                                      RSS    AIC
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age:diabetes 2570.8 1248.1
## <none>                                                            2558.7 1248.3
## 
## Step:  AIC=1248.11
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:triceps:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:glucose:pressure:triceps:pedigree:age:diabetes      1     1.144
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes      1     2.669
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes       1     7.007
## <none>                                                                    
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    31.501
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    41.628
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    61.978
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    64.878
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    80.694
##                                                                  RSS    AIC
## - pregnant:glucose:pressure:triceps:pedigree:age:diabetes     2571.9 1246.3
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes     2573.4 1246.5
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes      2577.8 1247.2
## <none>                                                        2570.8 1248.1
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2602.2 1250.9
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2612.4 1252.4
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2632.7 1255.5
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2635.6 1255.9
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2651.4 1258.3
## 
## Step:  AIC=1246.28
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes      1     3.332
## <none>                                                                    
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes       1    14.703
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    30.558
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    47.487
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    69.243
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    80.965
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    81.421
##                                                                  RSS    AIC
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes     2575.2 1244.8
## <none>                                                        2571.9 1246.3
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes      2586.6 1246.5
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2602.4 1248.9
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2619.4 1251.5
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2641.1 1254.7
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2652.9 1256.5
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2653.3 1256.5
## 
## Step:  AIC=1244.79
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes       1    11.541
## <none>                                                                    
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    38.609
## - pregnant:pressure:triceps:pedigree:age:diabetes              1    40.150
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    50.035
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    77.673
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    83.123
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    83.375
##                                                                  RSS    AIC
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes      2586.8 1244.5
## <none>                                                        2575.2 1244.8
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2613.8 1248.6
## - pregnant:pressure:triceps:pedigree:age:diabetes             2615.4 1248.9
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2625.3 1250.4
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2652.9 1254.5
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2658.3 1255.3
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2658.6 1255.3
## 
## Step:  AIC=1244.55
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:triceps:insulin:pedigree:age:diabetes               1     7.214
## <none>                                                                    
## - pregnant:glucose:triceps:pedigree:age:diabetes               1    28.025
## - pregnant:pressure:triceps:pedigree:age:diabetes              1    29.857
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    45.019
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    58.987
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    72.277
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    74.478
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    81.097
##                                                                  RSS    AIC
## - pregnant:triceps:insulin:pedigree:age:diabetes              2594.0 1243.7
## <none>                                                        2586.8 1244.5
## - pregnant:glucose:triceps:pedigree:age:diabetes              2614.8 1246.8
## - pregnant:pressure:triceps:pedigree:age:diabetes             2616.6 1247.1
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2631.8 1249.3
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2645.8 1251.4
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2659.0 1253.4
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2661.2 1253.7
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2667.9 1254.7
## 
## Step:  AIC=1243.65
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     glucose:triceps:insulin:pedigree:age:diabetes + pressure:triceps:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## <none>                                                                    
## - pregnant:pressure:triceps:pedigree:age:diabetes              1    25.472
## - pregnant:glucose:triceps:pedigree:age:diabetes               1    52.793
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    57.405
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    73.883
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    82.395
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    87.274
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    87.532
##                                                                  RSS    AIC
## <none>                                                        2594.0 1243.7
## - pregnant:pressure:triceps:pedigree:age:diabetes             2619.4 1245.5
## - pregnant:glucose:triceps:pedigree:age:diabetes              2646.8 1249.6
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2651.4 1250.2
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2667.9 1252.7
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2676.4 1253.9
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2681.2 1254.7
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2681.5 1254.7
summary(modMass)$adj.r.squared
## [1] 0.6297323
Classificazione NA

Il problema è che bisogna fare diversi modelli per i diversi casi di NA nelle altree variabili, procedo allora con una iniziale classificazione

naDf = as.data.frame(sapply(1:ncol(df),
                            function(c) is.na(df[,varDip]) & is.na(df[,c])))
names(naDf) = names(df)
# seleziono le colonne con almeno un NA
naDf = naDf[,sapply(1:ncol(naDf), function(c) sum(naDf[,c])>0)]
ftable(xtabs(mass ~ ., naDf))
##                  insulin FALSE TRUE
## pressure triceps                   
## FALSE    FALSE               1    1
##          TRUE                0    2
## TRUE     FALSE               0    0
##          TRUE                0    7

I modelli da costruire saranno 4.. Il codice di seguito prende un’osservazione NA, costruisce un modello escludendo altre variabili NA nella stessa osservazione e successivamente, attraverso il modello, predice il valora della variabile NA e lo sostituisce. Ovviamente non lo fa solo alla singola osservazione ma a tutte le osservazioni che si troveranno nella medesima situazione.

## Start:  AIC=2690.25
## mass ~ pregnant * glucose * pressure * pedigree * age * diabetes
## 
##                                                   Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:pedigree:age:diabetes  1    30.686 24531 2689.2
## <none>                                                         24500 2690.2
## 
## Step:  AIC=2689.16
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:pedigree:age       1     0.080 24531 2687.2
## - pregnant:glucose:pressure:age:diabetes       1     4.791 24535 2687.3
## - pregnant:pressure:pedigree:age:diabetes      1     9.505 24540 2687.4
## <none>                                                     24531 2689.2
## - glucose:pressure:pedigree:age:diabetes       1    81.857 24612 2689.6
## - pregnant:glucose:pedigree:age:diabetes       1   124.620 24655 2690.9
## - pregnant:glucose:pressure:pedigree:diabetes  1   229.109 24760 2693.9
## 
## Step:  AIC=2687.16
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:age:diabetes       1     5.065 24536 2685.3
## - pregnant:pressure:pedigree:age:diabetes      1    10.253 24541 2685.5
## <none>                                                     24531 2687.2
## - glucose:pressure:pedigree:age:diabetes       1    86.958 24618 2687.7
## - pregnant:glucose:pedigree:age:diabetes       1   125.401 24656 2688.9
## - pregnant:glucose:pressure:pedigree:diabetes  1   230.390 24761 2692.0
## 
## Step:  AIC=2685.32
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:pressure:pedigree:age:diabetes      1    10.922 24547 2683.6
## - pregnant:glucose:pressure:age                1    56.045 24592 2685.0
## <none>                                                     24536 2685.3
## - glucose:pressure:pedigree:age:diabetes       1    85.606 24621 2685.8
## - pregnant:glucose:pedigree:age:diabetes       1   129.107 24665 2687.1
## - pregnant:glucose:pressure:pedigree:diabetes  1   233.662 24769 2690.2
## 
## Step:  AIC=2683.64
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:pressure:pedigree:age               1     6.917 24554 2681.8
## - pregnant:pressure:age:diabetes               1    27.611 24574 2682.5
## - pregnant:glucose:pressure:age                1    56.953 24604 2683.3
## <none>                                                     24547 2683.6
## - glucose:pressure:pedigree:age:diabetes       1    81.849 24628 2684.1
## - pregnant:glucose:pedigree:age:diabetes       1   141.836 24688 2685.8
## - pregnant:glucose:pressure:pedigree:diabetes  1   225.551 24772 2688.3
## 
## Step:  AIC=2681.85
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:pressure:age:diabetes               1    39.924 24593 2681.0
## - pregnant:glucose:pressure:age                1    55.486 24609 2681.5
## <none>                                                     24554 2681.8
## - glucose:pressure:pedigree:age:diabetes       1    85.733 24639 2682.4
## - pregnant:glucose:pedigree:age:diabetes       1   149.924 24703 2684.3
## - pregnant:glucose:pressure:pedigree:diabetes  1   221.124 24775 2686.4
## 
## Step:  AIC=2681.03
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:age                1    25.634 24619 2679.8
## <none>                                                     24593 2681.0
## - glucose:pressure:pedigree:age:diabetes       1    80.000 24673 2681.4
## - pregnant:glucose:pedigree:age:diabetes       1   153.101 24747 2683.6
## - pregnant:glucose:pressure:pedigree:diabetes  1   202.867 24796 2685.0
## 
## Step:  AIC=2679.79
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + pregnant:pressure:age + 
##     glucose:pressure:age + pregnant:pedigree:age + glucose:pedigree:age + 
##     pressure:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:pressure:age                        1    35.271 24654 2678.8
## <none>                                                     24619 2679.8
## - glucose:pressure:pedigree:age:diabetes       1    87.964 24707 2680.4
## - pregnant:glucose:pedigree:age:diabetes       1   159.929 24779 2682.5
## - pregnant:glucose:pressure:pedigree:diabetes  1   198.050 24817 2683.6
## 
## Step:  AIC=2678.83
## mass ~ pregnant + glucose + pressure + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:pedigree + glucose:pedigree + pressure:pedigree + 
##     pregnant:age + glucose:age + pressure:age + pedigree:age + 
##     pregnant:diabetes + glucose:diabetes + pressure:diabetes + 
##     pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:glucose:age + glucose:pressure:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + pressure:pedigree:diabetes + 
##     pregnant:age:diabetes + glucose:age:diabetes + pressure:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:pedigree + 
##     pregnant:glucose:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## <none>                                                     24654 2678.8
## - glucose:pressure:pedigree:age:diabetes       1    80.627 24735 2679.2
## - pregnant:glucose:pedigree:age:diabetes       1   161.962 24816 2681.6
## - pregnant:glucose:pressure:pedigree:diabetes  1   194.838 24849 2682.6
## Start:  AIC=2835.34
## mass ~ pregnant * glucose * pedigree * age * diabetes
## 
##                                          Df Sum of Sq   RSS    AIC
## <none>                                                29241 2835.3
## - pregnant:glucose:pedigree:age:diabetes  1    177.51 29418 2837.9
## Start:  AIC=1748.44
## mass ~ pregnant * glucose * pressure * triceps * pedigree * age * 
##     diabetes
## 
##                                                           Df Sum of Sq    RSS
## <none>                                                                 8649.2
## - pregnant:glucose:pressure:triceps:pedigree:age:diabetes  1    49.715 8698.9
##                                                              AIC
## <none>                                                    1748.4
## - pregnant:glucose:pressure:triceps:pedigree:age:diabetes 1749.5
## Start:  AIC=1248.26
## mass ~ pregnant * glucose * pressure * triceps * insulin * pedigree * 
##     age * diabetes
## 
##                                                                   Df Sum of Sq
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age:diabetes  1    12.052
## <none>                                                                        
##                                                                      RSS    AIC
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age:diabetes 2570.8 1248.1
## <none>                                                            2558.7 1248.3
## 
## Step:  AIC=1248.11
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:triceps:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:glucose:pressure:triceps:pedigree:age:diabetes      1     1.144
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes      1     2.669
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes       1     7.007
## <none>                                                                    
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    31.501
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    41.628
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    61.978
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    64.878
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    80.694
##                                                                  RSS    AIC
## - pregnant:glucose:pressure:triceps:pedigree:age:diabetes     2571.9 1246.3
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes     2573.4 1246.5
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes      2577.8 1247.2
## <none>                                                        2570.8 1248.1
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2602.2 1250.9
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2612.4 1252.4
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2632.7 1255.5
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2635.6 1255.9
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2651.4 1258.3
## 
## Step:  AIC=1246.28
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes      1     3.332
## <none>                                                                    
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes       1    14.703
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    30.558
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    47.487
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    69.243
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    80.965
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    81.421
##                                                                  RSS    AIC
## - pregnant:pressure:triceps:insulin:pedigree:age:diabetes     2575.2 1244.8
## <none>                                                        2571.9 1246.3
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes      2586.6 1246.5
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2602.4 1248.9
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2619.4 1251.5
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2641.1 1254.7
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2652.9 1256.5
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2653.3 1256.5
## 
## Step:  AIC=1244.79
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes       1    11.541
## <none>                                                                    
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    38.609
## - pregnant:pressure:triceps:pedigree:age:diabetes              1    40.150
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    50.035
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    77.673
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    83.123
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    83.375
##                                                                  RSS    AIC
## - pregnant:glucose:triceps:insulin:pedigree:age:diabetes      2586.8 1244.5
## <none>                                                        2575.2 1244.8
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2613.8 1248.6
## - pregnant:pressure:triceps:pedigree:age:diabetes             2615.4 1248.9
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2625.3 1250.4
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2652.9 1254.5
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2658.3 1255.3
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2658.6 1255.3
## 
## Step:  AIC=1244.55
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:triceps:insulin:pedigree:age:diabetes + glucose:triceps:insulin:pedigree:age:diabetes + 
##     pressure:triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## - pregnant:triceps:insulin:pedigree:age:diabetes               1     7.214
## <none>                                                                    
## - pregnant:glucose:triceps:pedigree:age:diabetes               1    28.025
## - pregnant:pressure:triceps:pedigree:age:diabetes              1    29.857
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    45.019
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    58.987
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    72.277
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    74.478
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    81.097
##                                                                  RSS    AIC
## - pregnant:triceps:insulin:pedigree:age:diabetes              2594.0 1243.7
## <none>                                                        2586.8 1244.5
## - pregnant:glucose:triceps:pedigree:age:diabetes              2614.8 1246.8
## - pregnant:pressure:triceps:pedigree:age:diabetes             2616.6 1247.1
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2631.8 1249.3
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2645.8 1251.4
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2659.0 1253.4
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2661.2 1253.7
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2667.9 1254.7
## 
## Step:  AIC=1243.65
## mass ~ pregnant + glucose + pressure + triceps + insulin + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:triceps + glucose:triceps + pressure:triceps + pregnant:insulin + 
##     glucose:insulin + pressure:insulin + triceps:insulin + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + triceps:pedigree + 
##     insulin:pedigree + pregnant:age + glucose:age + pressure:age + 
##     triceps:age + insulin:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + triceps:diabetes + 
##     insulin:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:triceps + pregnant:pressure:triceps + glucose:pressure:triceps + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:triceps:insulin + glucose:triceps:insulin + pressure:triceps:insulin + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:triceps:pedigree + glucose:triceps:pedigree + 
##     pressure:triceps:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + triceps:insulin:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:triceps:age + 
##     glucose:triceps:age + pressure:triceps:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + triceps:insulin:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     triceps:pedigree:age + insulin:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:triceps:diabetes + glucose:triceps:diabetes + pressure:triceps:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     triceps:insulin:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + triceps:pedigree:diabetes + 
##     insulin:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + triceps:age:diabetes + insulin:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:triceps + 
##     pregnant:glucose:pressure:insulin + pregnant:glucose:triceps:insulin + 
##     pregnant:pressure:triceps:insulin + glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:triceps:pedigree + 
##     pregnant:pressure:triceps:pedigree + glucose:pressure:triceps:pedigree + 
##     pregnant:glucose:insulin:pedigree + pregnant:pressure:insulin:pedigree + 
##     glucose:pressure:insulin:pedigree + pregnant:triceps:insulin:pedigree + 
##     glucose:triceps:insulin:pedigree + pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:triceps:age + 
##     pregnant:pressure:triceps:age + glucose:pressure:triceps:age + 
##     pregnant:glucose:insulin:age + pregnant:pressure:insulin:age + 
##     glucose:pressure:insulin:age + pregnant:triceps:insulin:age + 
##     glucose:triceps:insulin:age + pressure:triceps:insulin:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:triceps:pedigree:age + 
##     glucose:triceps:pedigree:age + pressure:triceps:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:triceps:diabetes + 
##     pregnant:pressure:triceps:diabetes + glucose:pressure:triceps:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:triceps:insulin:diabetes + 
##     glucose:triceps:insulin:diabetes + pressure:triceps:insulin:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:triceps:pedigree:diabetes + 
##     glucose:triceps:pedigree:diabetes + pressure:triceps:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:triceps:age:diabetes + 
##     glucose:triceps:age:diabetes + pressure:triceps:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + triceps:insulin:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + triceps:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin + 
##     pregnant:glucose:pressure:triceps:pedigree + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:triceps:insulin:pedigree + pregnant:pressure:triceps:insulin:pedigree + 
##     glucose:pressure:triceps:insulin:pedigree + pregnant:glucose:pressure:triceps:age + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:triceps:insulin:age + 
##     pregnant:pressure:triceps:insulin:age + glucose:pressure:triceps:insulin:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:triceps:pedigree:age + 
##     pregnant:pressure:triceps:pedigree:age + glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:triceps:insulin:pedigree:age + 
##     glucose:triceps:insulin:pedigree:age + pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:diabetes + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:triceps:insulin:diabetes + pregnant:pressure:triceps:insulin:diabetes + 
##     glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:triceps:pedigree:diabetes + pregnant:pressure:triceps:pedigree:diabetes + 
##     glucose:pressure:triceps:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:triceps:insulin:pedigree:diabetes + glucose:triceps:insulin:pedigree:diabetes + 
##     pressure:triceps:insulin:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:triceps:age:diabetes + pregnant:pressure:triceps:age:diabetes + 
##     glucose:pressure:triceps:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:triceps:insulin:age:diabetes + glucose:triceps:insulin:age:diabetes + 
##     pressure:triceps:insulin:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:triceps:pedigree:age:diabetes + glucose:triceps:pedigree:age:diabetes + 
##     pressure:triceps:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     triceps:insulin:pedigree:age:diabetes + pregnant:glucose:pressure:triceps:insulin:pedigree + 
##     pregnant:glucose:pressure:triceps:insulin:age + pregnant:glucose:pressure:triceps:pedigree:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:triceps:insulin:pedigree:age + 
##     pregnant:pressure:triceps:insulin:pedigree:age + glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:diabetes + pregnant:glucose:pressure:triceps:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:triceps:insulin:pedigree:diabetes + 
##     pregnant:pressure:triceps:insulin:pedigree:diabetes + glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:age:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:triceps:insulin:age:diabetes + pregnant:pressure:triceps:insulin:age:diabetes + 
##     glucose:pressure:triceps:insulin:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:triceps:pedigree:age:diabetes + pregnant:pressure:triceps:pedigree:age:diabetes + 
##     glucose:pressure:triceps:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     glucose:triceps:insulin:pedigree:age:diabetes + pressure:triceps:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:age + 
##     pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes + 
##     pregnant:glucose:pressure:triceps:insulin:age:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     glucose:pressure:triceps:insulin:pedigree:age:diabetes
## 
##                                                               Df Sum of Sq
## <none>                                                                    
## - pregnant:pressure:triceps:pedigree:age:diabetes              1    25.472
## - pregnant:glucose:triceps:pedigree:age:diabetes               1    52.793
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes       1    57.405
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age       1    73.883
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes  1    82.395
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes      1    87.274
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes       1    87.532
##                                                                  RSS    AIC
## <none>                                                        2594.0 1243.7
## - pregnant:pressure:triceps:pedigree:age:diabetes             2619.4 1245.5
## - pregnant:glucose:triceps:pedigree:age:diabetes              2646.8 1249.6
## - pregnant:glucose:pressure:triceps:insulin:age:diabetes      2651.4 1250.2
## - pregnant:glucose:pressure:triceps:insulin:pedigree:age      2667.9 1252.7
## - pregnant:glucose:pressure:triceps:insulin:pedigree:diabetes 2676.4 1253.9
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes     2681.2 1254.7
## - glucose:pressure:triceps:insulin:pedigree:age:diabetes      2681.5 1254.7

Pressure

## Start:  AIC=2008.65
## pressure ~ pregnant * glucose * triceps * insulin * mass * pedigree * 
##     age * diabetes
## 
##                                                               Df Sum of Sq
## <none>                                                                    
## - pregnant:glucose:triceps:insulin:mass:pedigree:age:diabetes  1    126.97
##                                                                 RSS    AIC
## <none>                                                        17588 2008.7
## - pregnant:glucose:triceps:insulin:mass:pedigree:age:diabetes 17715 2009.5
naDf = as.data.frame(sapply(1:ncol(df),
                            function(c) is.na(df[,varDip]) & is.na(df[,c])))
names(naDf) = names(df)
# seleziono le colonne con almeno un NA
naDf = naDf[,sapply(1:ncol(naDf), function(c) sum(naDf[,c])>0)]
ftable(xtabs(get(varDip) ~ ., naDf))
##                  insulin FALSE TRUE
## pressure triceps                   
## FALSE    FALSE               0    0
##          TRUE                0    0
## TRUE     FALSE               0    2
##          TRUE                0   33
## Start:  AIC=3580.45
## pressure ~ pregnant * glucose * mass * pedigree * age * diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:mass:pedigree:age:diabetes  1    43.863 81447 3578.8
## <none>                                                     81403 3580.4
## 
## Step:  AIC=3578.84
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes
## 
##                                           Df Sum of Sq   RSS    AIC
## - glucose:mass:pedigree:age:diabetes       1      6.36 81453 3576.9
## - pregnant:glucose:mass:age:diabetes       1     27.84 81475 3577.1
## - pregnant:glucose:mass:pedigree:diabetes  1     63.83 81511 3577.4
## - pregnant:glucose:pedigree:age:diabetes   1    141.12 81588 3578.1
## <none>                                                 81447 3578.8
## - pregnant:mass:pedigree:age:diabetes      1    252.26 81699 3579.1
## - pregnant:glucose:mass:pedigree:age       1    636.35 82083 3582.5
## 
## Step:  AIC=3576.9
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes
## 
##                                           Df Sum of Sq   RSS    AIC
## - pregnant:glucose:mass:age:diabetes       1     35.38 81489 3575.2
## - pregnant:glucose:mass:pedigree:diabetes  1     64.34 81518 3575.5
## - pregnant:glucose:pedigree:age:diabetes   1    146.02 81599 3576.2
## <none>                                                 81453 3576.9
## - pregnant:mass:pedigree:age:diabetes      1    278.98 81732 3577.4
## - pregnant:glucose:mass:pedigree:age       1    838.79 82292 3582.4
## 
## Step:  AIC=3575.22
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes
## 
##                                           Df Sum of Sq   RSS    AIC
## - glucose:mass:age:diabetes                1     77.60 81566 3573.9
## - pregnant:glucose:mass:pedigree:diabetes  1     81.52 81570 3573.9
## - pregnant:glucose:pedigree:age:diabetes   1    153.77 81642 3574.6
## <none>                                                 81489 3575.2
## - pregnant:mass:pedigree:age:diabetes      1    280.65 81769 3575.7
## - pregnant:glucose:mass:pedigree:age       1    803.64 82292 3580.4
## 
## Step:  AIC=3573.91
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes
## 
##                                           Df Sum of Sq   RSS    AIC
## - pregnant:glucose:mass:pedigree:diabetes  1     77.94 81644 3572.6
## - pregnant:glucose:pedigree:age:diabetes   1    155.82 81722 3573.3
## <none>                                                 81566 3573.9
## - pregnant:mass:pedigree:age:diabetes      1    264.78 81831 3574.3
## - pregnant:glucose:mass:pedigree:age       1    771.51 82338 3578.8
## 
## Step:  AIC=3572.61
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes
## 
##                                          Df Sum of Sq   RSS    AIC
## - pregnant:glucose:mass:diabetes          1      0.04 81644 3570.6
## - pregnant:glucose:pedigree:age:diabetes  1    122.56 81767 3571.7
## - glucose:mass:pedigree:diabetes          1    184.29 81828 3572.3
## <none>                                                81644 3572.6
## - pregnant:mass:pedigree:age:diabetes     1    299.49 81944 3573.3
## - pregnant:glucose:mass:pedigree:age      1   1055.56 82700 3580.0
## 
## Step:  AIC=3570.61
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes
## 
##                                          Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pedigree:age:diabetes  1    123.26 81767 3569.7
## - glucose:mass:pedigree:diabetes          1    184.61 81829 3570.3
## <none>                                                81644 3570.6
## - pregnant:mass:pedigree:age:diabetes     1    299.54 81944 3571.3
## - pregnant:glucose:mass:pedigree:age      1   1069.12 82713 3578.2
## 
## Step:  AIC=3569.72
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:glucose:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:mass:pedigree:age:diabetes
## 
##                                       Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pedigree:diabetes   1      2.17 81770 3567.7
## - pregnant:glucose:age:diabetes        1      3.40 81771 3567.8
## - glucose:pedigree:age:diabetes        1      3.63 81771 3567.8
## - glucose:mass:pedigree:diabetes       1    220.73 81988 3569.7
## <none>                                             81767 3569.7
## - pregnant:mass:pedigree:age:diabetes  1    341.84 82109 3570.8
## - pregnant:glucose:mass:pedigree:age   1   1005.76 82773 3576.7
## 
## Step:  AIC=3567.74
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:age:diabetes
## 
##                                       Df Sum of Sq   RSS    AIC
## - glucose:pedigree:age:diabetes        1      1.89 81771 3565.8
## - pregnant:glucose:age:diabetes        1      3.26 81773 3565.8
## - glucose:mass:pedigree:diabetes       1    218.77 81988 3567.7
## <none>                                             81770 3567.7
## - pregnant:mass:pedigree:age:diabetes  1    339.82 82109 3568.8
## - pregnant:glucose:mass:pedigree:age   1   1005.70 82775 3574.7
## 
## Step:  AIC=3565.76
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:mass:pedigree:age:diabetes
## 
##                                       Df Sum of Sq   RSS    AIC
## - pregnant:glucose:age:diabetes        1      2.91 81774 3563.8
## - glucose:mass:pedigree:diabetes       1    219.13 81991 3565.7
## <none>                                             81771 3565.8
## - pregnant:mass:pedigree:age:diabetes  1    340.33 82112 3566.8
## - pregnant:glucose:mass:pedigree:age   1   1004.82 82776 3572.7
## 
## Step:  AIC=3563.78
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:glucose:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:age:diabetes
## 
##                                       Df Sum of Sq   RSS    AIC
## - pregnant:glucose:diabetes            1    114.20 81889 3562.8
## - glucose:age:diabetes                 1    117.48 81892 3562.8
## <none>                                             81774 3563.8
## - glucose:mass:pedigree:diabetes       1    223.98 81998 3563.8
## - pregnant:mass:pedigree:age:diabetes  1    357.87 82132 3565.0
## - pregnant:glucose:mass:pedigree:age   1   1003.27 82778 3570.7
## 
## Step:  AIC=3562.81
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:mass:diabetes + glucose:mass:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + mass:age:diabetes + pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree + pregnant:glucose:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pregnant:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age + pregnant:mass:pedigree:age:diabetes
## 
##                                       Df Sum of Sq   RSS    AIC
## - glucose:age:diabetes                 1     48.75 81937 3561.2
## - glucose:mass:pedigree:diabetes       1    217.39 82106 3562.7
## <none>                                             81889 3562.8
## - pregnant:mass:pedigree:age:diabetes  1    418.19 82307 3564.5
## - pregnant:glucose:mass:pedigree:age   1    975.21 82864 3569.5
## 
## Step:  AIC=3561.24
## pressure ~ pregnant + glucose + mass + pedigree + age + diabetes + 
##     pregnant:glucose + pregnant:mass + glucose:mass + pregnant:pedigree + 
##     glucose:pedigree + mass:pedigree + pregnant:age + glucose:age + 
##     mass:age + pedigree:age + pregnant:diabetes + glucose:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:mass + 
##     pregnant:glucose:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pregnant:glucose:age + pregnant:mass:age + glucose:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + mass:pedigree:age + 
##     pregnant:mass:diabetes + glucose:mass:diabetes + pregnant:pedigree:diabetes + 
##     glucose:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     mass:age:diabetes + pedigree:age:diabetes + pregnant:glucose:mass:pedigree + 
##     pregnant:glucose:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pregnant:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age + 
##     pregnant:mass:pedigree:age:diabetes
## 
##                                       Df Sum of Sq   RSS    AIC
## <none>                                             81937 3561.2
## - glucose:mass:pedigree:diabetes       1    241.07 82178 3561.4
## - pregnant:mass:pedigree:age:diabetes  1    460.68 82398 3563.4
## - pregnant:glucose:mass:pedigree:age   1   1001.54 82939 3568.1
## Start:  AIC=2692.64
## pressure ~ pregnant * glucose * triceps * mass * pedigree * age * 
##     diabetes
## 
##                                                       Df Sum of Sq   RSS    AIC
## <none>                                                             49533 2692.6
## - pregnant:glucose:triceps:mass:pedigree:age:diabetes  1    191.45 49724 2692.7

Triceps

## Start:  AIC=1673.66
## triceps ~ pregnant * glucose * pressure * insulin * mass * pedigree * 
##     age * diabetes
## 
##                                                                Df Sum of Sq
## - pregnant:glucose:pressure:insulin:mass:pedigree:age:diabetes  1    7.7648
## <none>                                                                     
##                                                                   RSS    AIC
## - pregnant:glucose:pressure:insulin:mass:pedigree:age:diabetes 7523.3 1672.1
## <none>                                                         7515.5 1673.7
## 
## Step:  AIC=1672.07
## triceps ~ pregnant + glucose + pressure + insulin + mass + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:insulin + glucose:insulin + pressure:insulin + pregnant:mass + 
##     glucose:mass + pressure:mass + insulin:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + insulin:pedigree + 
##     mass:pedigree + pregnant:age + glucose:age + pressure:age + 
##     insulin:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + insulin:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:glucose:mass + pregnant:pressure:mass + glucose:pressure:mass + 
##     pregnant:insulin:mass + glucose:insulin:mass + pressure:insulin:mass + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pressure:mass:pedigree + insulin:mass:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + pregnant:mass:age + 
##     glucose:mass:age + pressure:mass:age + insulin:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     insulin:pedigree:age + mass:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     pregnant:mass:diabetes + glucose:mass:diabetes + pressure:mass:diabetes + 
##     insulin:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + insulin:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + insulin:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:insulin + 
##     pregnant:glucose:pressure:mass + pregnant:glucose:insulin:mass + 
##     pregnant:pressure:insulin:mass + glucose:pressure:insulin:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:insulin:pedigree + 
##     pregnant:pressure:insulin:pedigree + glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:mass:pedigree + pregnant:pressure:mass:pedigree + 
##     glucose:pressure:mass:pedigree + pregnant:insulin:mass:pedigree + 
##     glucose:insulin:mass:pedigree + pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:insulin:age + 
##     pregnant:pressure:insulin:age + glucose:pressure:insulin:age + 
##     pregnant:glucose:mass:age + pregnant:pressure:mass:age + 
##     glucose:pressure:mass:age + pregnant:insulin:mass:age + glucose:insulin:mass:age + 
##     pressure:insulin:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     insulin:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:insulin:mass:diabetes + glucose:insulin:mass:diabetes + 
##     pressure:insulin:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     insulin:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     insulin:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:insulin:mass:pedigree + 
##     pregnant:pressure:insulin:mass:pedigree + glucose:pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:insulin:mass:age + pregnant:pressure:insulin:mass:age + 
##     glucose:pressure:insulin:mass:age + pregnant:glucose:pressure:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:insulin:mass:pedigree:age + glucose:insulin:mass:pedigree:age + 
##     pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:insulin:mass:diabetes + 
##     pregnant:pressure:insulin:mass:diabetes + glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:insulin:mass:pedigree:diabetes + 
##     glucose:insulin:mass:pedigree:diabetes + pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:insulin:mass:age:diabetes + 
##     glucose:insulin:mass:age:diabetes + pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree + pregnant:glucose:pressure:insulin:mass:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:insulin:mass:pedigree:age + pregnant:pressure:insulin:mass:pedigree:age + 
##     glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:insulin:mass:pedigree:diabetes + pregnant:pressure:insulin:mass:pedigree:diabetes + 
##     glucose:pressure:insulin:mass:pedigree:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:insulin:mass:age:diabetes + 
##     pregnant:pressure:insulin:mass:age:diabetes + glucose:pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes + pregnant:insulin:mass:pedigree:age:diabetes + 
##     glucose:insulin:mass:pedigree:age:diabetes + pressure:insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:age:diabetes + pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:pedigree:age:diabetes + pregnant:glucose:insulin:mass:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:mass:pedigree:age:diabetes + glucose:pressure:insulin:mass:pedigree:age:diabetes
## 
##                                                            Df Sum of Sq    RSS
## - glucose:pressure:insulin:mass:pedigree:age:diabetes       1     1.140 7524.4
## - pregnant:pressure:insulin:mass:pedigree:age:diabetes      1     1.575 7524.9
## - pregnant:glucose:pressure:insulin:mass:age:diabetes       1    29.251 7552.5
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes      1    32.183 7555.5
## <none>                                                                  7523.3
## - pregnant:glucose:pressure:insulin:mass:pedigree:age       1    64.513 7587.8
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes  1    72.519 7595.8
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes   1   110.848 7634.1
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes       1   167.315 7690.6
##                                                               AIC
## - glucose:pressure:insulin:mass:pedigree:age:diabetes      1670.1
## - pregnant:pressure:insulin:mass:pedigree:age:diabetes     1670.2
## - pregnant:glucose:pressure:insulin:mass:age:diabetes      1671.6
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes     1671.8
## <none>                                                     1672.1
## - pregnant:glucose:pressure:insulin:mass:pedigree:age      1673.4
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes 1673.8
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes  1675.8
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes      1678.7
## 
## Step:  AIC=1670.13
## triceps ~ pregnant + glucose + pressure + insulin + mass + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:insulin + glucose:insulin + pressure:insulin + pregnant:mass + 
##     glucose:mass + pressure:mass + insulin:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + insulin:pedigree + 
##     mass:pedigree + pregnant:age + glucose:age + pressure:age + 
##     insulin:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + insulin:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:glucose:mass + pregnant:pressure:mass + glucose:pressure:mass + 
##     pregnant:insulin:mass + glucose:insulin:mass + pressure:insulin:mass + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pressure:mass:pedigree + insulin:mass:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + pregnant:mass:age + 
##     glucose:mass:age + pressure:mass:age + insulin:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     insulin:pedigree:age + mass:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     pregnant:mass:diabetes + glucose:mass:diabetes + pressure:mass:diabetes + 
##     insulin:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + insulin:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + insulin:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:insulin + 
##     pregnant:glucose:pressure:mass + pregnant:glucose:insulin:mass + 
##     pregnant:pressure:insulin:mass + glucose:pressure:insulin:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:insulin:pedigree + 
##     pregnant:pressure:insulin:pedigree + glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:mass:pedigree + pregnant:pressure:mass:pedigree + 
##     glucose:pressure:mass:pedigree + pregnant:insulin:mass:pedigree + 
##     glucose:insulin:mass:pedigree + pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:insulin:age + 
##     pregnant:pressure:insulin:age + glucose:pressure:insulin:age + 
##     pregnant:glucose:mass:age + pregnant:pressure:mass:age + 
##     glucose:pressure:mass:age + pregnant:insulin:mass:age + glucose:insulin:mass:age + 
##     pressure:insulin:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     insulin:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:insulin:mass:diabetes + glucose:insulin:mass:diabetes + 
##     pressure:insulin:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     insulin:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     insulin:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:insulin:mass:pedigree + 
##     pregnant:pressure:insulin:mass:pedigree + glucose:pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:insulin:mass:age + pregnant:pressure:insulin:mass:age + 
##     glucose:pressure:insulin:mass:age + pregnant:glucose:pressure:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:insulin:mass:pedigree:age + glucose:insulin:mass:pedigree:age + 
##     pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:insulin:mass:diabetes + 
##     pregnant:pressure:insulin:mass:diabetes + glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:insulin:mass:pedigree:diabetes + 
##     glucose:insulin:mass:pedigree:diabetes + pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:insulin:mass:age:diabetes + 
##     glucose:insulin:mass:age:diabetes + pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree + pregnant:glucose:pressure:insulin:mass:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:insulin:mass:pedigree:age + pregnant:pressure:insulin:mass:pedigree:age + 
##     glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:insulin:mass:pedigree:diabetes + pregnant:pressure:insulin:mass:pedigree:diabetes + 
##     glucose:pressure:insulin:mass:pedigree:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:insulin:mass:age:diabetes + 
##     pregnant:pressure:insulin:mass:age:diabetes + glucose:pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes + pregnant:insulin:mass:pedigree:age:diabetes + 
##     glucose:insulin:mass:pedigree:age:diabetes + pressure:insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:age:diabetes + pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:pedigree:age:diabetes + pregnant:glucose:insulin:mass:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:mass:pedigree:age:diabetes
## 
##                                                            Df Sum of Sq    RSS
## - pregnant:pressure:insulin:mass:pedigree:age:diabetes      1     0.768 7525.2
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes      1    33.783 7558.2
## <none>                                                                  7524.4
## - pregnant:glucose:pressure:insulin:mass:age:diabetes       1    56.062 7580.5
## - pregnant:glucose:pressure:insulin:mass:pedigree:age       1    76.500 7600.9
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes  1    85.913 7610.3
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes       1   192.085 7716.5
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes   1   242.126 7766.5
##                                                               AIC
## - pregnant:pressure:insulin:mass:pedigree:age:diabetes     1668.2
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes     1669.9
## <none>                                                     1670.1
## - pregnant:glucose:pressure:insulin:mass:age:diabetes      1671.0
## - pregnant:glucose:pressure:insulin:mass:pedigree:age      1672.1
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes 1672.6
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes      1678.1
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes  1680.6
## 
## Step:  AIC=1668.17
## triceps ~ pregnant + glucose + pressure + insulin + mass + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:insulin + glucose:insulin + pressure:insulin + pregnant:mass + 
##     glucose:mass + pressure:mass + insulin:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + insulin:pedigree + 
##     mass:pedigree + pregnant:age + glucose:age + pressure:age + 
##     insulin:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + insulin:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:glucose:mass + pregnant:pressure:mass + glucose:pressure:mass + 
##     pregnant:insulin:mass + glucose:insulin:mass + pressure:insulin:mass + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pressure:mass:pedigree + insulin:mass:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + pregnant:mass:age + 
##     glucose:mass:age + pressure:mass:age + insulin:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     insulin:pedigree:age + mass:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     pregnant:mass:diabetes + glucose:mass:diabetes + pressure:mass:diabetes + 
##     insulin:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + insulin:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + insulin:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:insulin + 
##     pregnant:glucose:pressure:mass + pregnant:glucose:insulin:mass + 
##     pregnant:pressure:insulin:mass + glucose:pressure:insulin:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:insulin:pedigree + 
##     pregnant:pressure:insulin:pedigree + glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:mass:pedigree + pregnant:pressure:mass:pedigree + 
##     glucose:pressure:mass:pedigree + pregnant:insulin:mass:pedigree + 
##     glucose:insulin:mass:pedigree + pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:insulin:age + 
##     pregnant:pressure:insulin:age + glucose:pressure:insulin:age + 
##     pregnant:glucose:mass:age + pregnant:pressure:mass:age + 
##     glucose:pressure:mass:age + pregnant:insulin:mass:age + glucose:insulin:mass:age + 
##     pressure:insulin:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     insulin:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:insulin:mass:diabetes + glucose:insulin:mass:diabetes + 
##     pressure:insulin:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     insulin:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     insulin:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:insulin:mass:pedigree + 
##     pregnant:pressure:insulin:mass:pedigree + glucose:pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:insulin:mass:age + pregnant:pressure:insulin:mass:age + 
##     glucose:pressure:insulin:mass:age + pregnant:glucose:pressure:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:insulin:mass:pedigree:age + glucose:insulin:mass:pedigree:age + 
##     pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:insulin:mass:diabetes + 
##     pregnant:pressure:insulin:mass:diabetes + glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:insulin:mass:pedigree:diabetes + 
##     glucose:insulin:mass:pedigree:diabetes + pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:insulin:mass:age:diabetes + 
##     glucose:insulin:mass:age:diabetes + pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree + pregnant:glucose:pressure:insulin:mass:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:insulin:mass:pedigree:age + pregnant:pressure:insulin:mass:pedigree:age + 
##     glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:insulin:mass:pedigree:diabetes + pregnant:pressure:insulin:mass:pedigree:diabetes + 
##     glucose:pressure:insulin:mass:pedigree:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:insulin:mass:age:diabetes + 
##     pregnant:pressure:insulin:mass:age:diabetes + glucose:pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes + pregnant:insulin:mass:pedigree:age:diabetes + 
##     glucose:insulin:mass:pedigree:age:diabetes + pressure:insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:age:diabetes + pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:pedigree:age:diabetes + pregnant:glucose:insulin:mass:pedigree:age:diabetes
## 
##                                                            Df Sum of Sq    RSS
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes      1     33.83 7559.0
## <none>                                                                  7525.2
## - pregnant:glucose:pressure:insulin:mass:age:diabetes       1     68.29 7593.5
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes  1     88.77 7614.0
## - pregnant:glucose:pressure:insulin:mass:pedigree:age       1    100.96 7626.1
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes       1    192.41 7717.6
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes   1    243.67 7768.9
## - pressure:insulin:mass:pedigree:age:diabetes               1    331.25 7856.4
##                                                               AIC
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes     1667.9
## <none>                                                     1668.2
## - pregnant:glucose:pressure:insulin:mass:age:diabetes      1669.7
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes 1670.8
## - pregnant:glucose:pressure:insulin:mass:pedigree:age      1671.4
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes      1676.1
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes  1678.7
## - pressure:insulin:mass:pedigree:age:diabetes              1683.1
## 
## Step:  AIC=1667.93
## triceps ~ pregnant + glucose + pressure + insulin + mass + pedigree + 
##     age + diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:insulin + glucose:insulin + pressure:insulin + pregnant:mass + 
##     glucose:mass + pressure:mass + insulin:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + insulin:pedigree + 
##     mass:pedigree + pregnant:age + glucose:age + pressure:age + 
##     insulin:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + insulin:diabetes + 
##     mass:diabetes + pedigree:diabetes + age:diabetes + pregnant:glucose:pressure + 
##     pregnant:glucose:insulin + pregnant:pressure:insulin + glucose:pressure:insulin + 
##     pregnant:glucose:mass + pregnant:pressure:mass + glucose:pressure:mass + 
##     pregnant:insulin:mass + glucose:insulin:mass + pressure:insulin:mass + 
##     pregnant:glucose:pedigree + pregnant:pressure:pedigree + 
##     glucose:pressure:pedigree + pregnant:insulin:pedigree + glucose:insulin:pedigree + 
##     pressure:insulin:pedigree + pregnant:mass:pedigree + glucose:mass:pedigree + 
##     pressure:mass:pedigree + insulin:mass:pedigree + pregnant:glucose:age + 
##     pregnant:pressure:age + glucose:pressure:age + pregnant:insulin:age + 
##     glucose:insulin:age + pressure:insulin:age + pregnant:mass:age + 
##     glucose:mass:age + pressure:mass:age + insulin:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     insulin:pedigree:age + mass:pedigree:age + pregnant:glucose:diabetes + 
##     pregnant:pressure:diabetes + glucose:pressure:diabetes + 
##     pregnant:insulin:diabetes + glucose:insulin:diabetes + pressure:insulin:diabetes + 
##     pregnant:mass:diabetes + glucose:mass:diabetes + pressure:mass:diabetes + 
##     insulin:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + insulin:pedigree:diabetes + 
##     mass:pedigree:diabetes + pregnant:age:diabetes + glucose:age:diabetes + 
##     pressure:age:diabetes + insulin:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:insulin + 
##     pregnant:glucose:pressure:mass + pregnant:glucose:insulin:mass + 
##     pregnant:pressure:insulin:mass + glucose:pressure:insulin:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:insulin:pedigree + 
##     pregnant:pressure:insulin:pedigree + glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:mass:pedigree + pregnant:pressure:mass:pedigree + 
##     glucose:pressure:mass:pedigree + pregnant:insulin:mass:pedigree + 
##     glucose:insulin:mass:pedigree + pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:insulin:age + 
##     pregnant:pressure:insulin:age + glucose:pressure:insulin:age + 
##     pregnant:glucose:mass:age + pregnant:pressure:mass:age + 
##     glucose:pressure:mass:age + pregnant:insulin:mass:age + glucose:insulin:mass:age + 
##     pressure:insulin:mass:age + pregnant:glucose:pedigree:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:insulin:pedigree:age + glucose:insulin:pedigree:age + 
##     pressure:insulin:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     insulin:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:insulin:diabetes + pregnant:pressure:insulin:diabetes + 
##     glucose:pressure:insulin:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:insulin:mass:diabetes + glucose:insulin:mass:diabetes + 
##     pressure:insulin:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:insulin:pedigree:diabetes + glucose:insulin:pedigree:diabetes + 
##     pressure:insulin:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     insulin:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:insulin:age:diabetes + glucose:insulin:age:diabetes + 
##     pressure:insulin:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     insulin:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     insulin:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass + pregnant:glucose:pressure:insulin:pedigree + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:insulin:mass:pedigree + 
##     pregnant:pressure:insulin:mass:pedigree + glucose:pressure:insulin:mass:pedigree + 
##     pregnant:glucose:pressure:insulin:age + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:insulin:mass:age + pregnant:pressure:insulin:mass:age + 
##     glucose:pressure:insulin:mass:age + pregnant:glucose:pressure:pedigree:age + 
##     pregnant:glucose:insulin:pedigree:age + pregnant:pressure:insulin:pedigree:age + 
##     glucose:pressure:insulin:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:insulin:mass:pedigree:age + glucose:insulin:mass:pedigree:age + 
##     pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:diabetes + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:insulin:mass:diabetes + 
##     pregnant:pressure:insulin:mass:diabetes + glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:insulin:pedigree:diabetes + 
##     pregnant:pressure:insulin:pedigree:diabetes + glucose:pressure:insulin:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:insulin:mass:pedigree:diabetes + 
##     glucose:insulin:mass:pedigree:diabetes + pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:insulin:age:diabetes + 
##     pregnant:pressure:insulin:age:diabetes + glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:insulin:mass:age:diabetes + 
##     glucose:insulin:mass:age:diabetes + pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:insulin:pedigree:age:diabetes + 
##     glucose:insulin:pedigree:age:diabetes + pressure:insulin:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree + pregnant:glucose:pressure:insulin:mass:age + 
##     pregnant:glucose:pressure:insulin:pedigree:age + pregnant:glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:insulin:mass:pedigree:age + pregnant:pressure:insulin:mass:pedigree:age + 
##     glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:diabetes + 
##     pregnant:glucose:pressure:insulin:pedigree:diabetes + pregnant:glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:insulin:mass:pedigree:diabetes + pregnant:pressure:insulin:mass:pedigree:diabetes + 
##     glucose:pressure:insulin:mass:pedigree:diabetes + pregnant:glucose:pressure:insulin:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:insulin:mass:age:diabetes + 
##     pregnant:pressure:insulin:mass:age:diabetes + glucose:pressure:insulin:mass:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age:diabetes + pregnant:glucose:insulin:pedigree:age:diabetes + 
##     pregnant:pressure:insulin:pedigree:age:diabetes + glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes + pregnant:insulin:mass:pedigree:age:diabetes + 
##     glucose:insulin:mass:pedigree:age:diabetes + pressure:insulin:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:pedigree:age + pregnant:glucose:pressure:insulin:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:insulin:mass:age:diabetes + pregnant:glucose:pressure:insulin:pedigree:age:diabetes + 
##     pregnant:glucose:insulin:mass:pedigree:age:diabetes
## 
##                                                            Df Sum of Sq    RSS
## <none>                                                                  7559.0
## - pregnant:glucose:pressure:insulin:mass:age:diabetes       1     45.08 7604.1
## - glucose:pressure:mass:pedigree:age:diabetes               1     82.34 7641.4
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes  1     93.20 7652.2
## - pregnant:glucose:pressure:insulin:mass:pedigree:age       1    116.53 7675.5
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes       1    158.86 7717.9
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes   1    212.46 7771.5
## - pressure:insulin:mass:pedigree:age:diabetes               1    297.51 7856.5
## - pregnant:pressure:mass:pedigree:age:diabetes              1    863.19 8422.2
##                                                               AIC
## <none>                                                     1667.9
## - pregnant:glucose:pressure:insulin:mass:age:diabetes      1668.3
## - glucose:pressure:mass:pedigree:age:diabetes              1670.2
## - pregnant:glucose:pressure:insulin:mass:pedigree:diabetes 1670.8
## - pregnant:glucose:pressure:insulin:mass:pedigree:age      1672.0
## - pregnant:glucose:insulin:mass:pedigree:age:diabetes      1674.1
## - pregnant:glucose:pressure:insulin:pedigree:age:diabetes  1676.8
## - pressure:insulin:mass:pedigree:age:diabetes              1681.1
## - pregnant:pressure:mass:pedigree:age:diabetes             1708.5
## Start:  AIC=2295.11
## triceps ~ pregnant * glucose * pressure * mass * pedigree * age * 
##     diabetes
## 
##                                                        Df Sum of Sq   RSS
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes  1    4.5938 23453
## <none>                                                              23449
##                                                           AIC
## - pregnant:glucose:pressure:mass:pedigree:age:diabetes 2293.2
## <none>                                                 2295.1
## 
## Step:  AIC=2293.22
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age:diabetes + 
##     pregnant:pressure:mass:pedigree:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                                    Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:mass:pedigree:diabetes  1     3.352 23457 2291.3
## - glucose:pressure:mass:pedigree:age:diabetes       1    11.373 23465 2291.5
## - pregnant:glucose:pressure:mass:pedigree:age       1    31.106 23484 2291.9
## - pregnant:glucose:pressure:pedigree:age:diabetes   1    32.086 23485 2291.9
## - pregnant:glucose:mass:pedigree:age:diabetes       1    46.359 23500 2292.3
## - pregnant:pressure:mass:pedigree:age:diabetes      1    68.016 23521 2292.8
## <none>                                                          23453 2293.2
## - pregnant:glucose:pressure:mass:age:diabetes       1   122.171 23575 2294.0
## 
## Step:  AIC=2291.29
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                                   Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:mass:pedigree:age      1    30.366 23487 2290.0
## - pregnant:glucose:pressure:pedigree:age:diabetes  1    32.528 23489 2290.0
## - pregnant:glucose:mass:pedigree:age:diabetes      1    45.483 23502 2290.3
## - glucose:pressure:mass:pedigree:age:diabetes      1    48.994 23506 2290.4
## - pregnant:pressure:mass:pedigree:age:diabetes     1    74.934 23532 2291.0
## <none>                                                         23457 2291.3
## - pregnant:glucose:pressure:mass:age:diabetes      1   120.006 23577 2292.1
## 
## Step:  AIC=2289.99
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:pedigree + pregnant:glucose:pressure:mass:age + 
##     pregnant:glucose:pressure:pedigree:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:pressure:pedigree:age:diabetes + pregnant:glucose:mass:pedigree:age:diabetes + 
##     pregnant:pressure:mass:pedigree:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                                   Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:mass:pedigree          1    32.598 23520 2288.7
## - pregnant:glucose:pressure:pedigree:age:diabetes  1    45.233 23532 2289.0
## - pregnant:pressure:mass:pedigree:age:diabetes     1    52.880 23540 2289.2
## - pregnant:glucose:mass:pedigree:age:diabetes      1    58.657 23546 2289.3
## <none>                                                         23487 2290.0
## - pregnant:glucose:pressure:mass:age:diabetes      1    90.508 23577 2290.1
## - glucose:pressure:mass:pedigree:age:diabetes      1   113.466 23600 2290.6
## 
## Step:  AIC=2288.74
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:glucose:pressure:pedigree:age + 
##     pregnant:glucose:mass:pedigree:age + pregnant:pressure:mass:pedigree:age + 
##     glucose:pressure:mass:pedigree:age + pregnant:glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:pressure:mass:pedigree:diabetes + glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:mass:age:diabetes + 
##     pregnant:pressure:mass:age:diabetes + glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes + 
##     glucose:mass:pedigree:age:diabetes + pressure:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:pressure:pedigree:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                                   Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:pedigree:age:diabetes  1    35.795 23555 2287.6
## - pregnant:pressure:mass:pedigree:age:diabetes     1    44.963 23565 2287.8
## - pregnant:glucose:mass:pedigree:age:diabetes      1    50.270 23570 2287.9
## <none>                                                         23520 2288.7
## - pregnant:glucose:pressure:mass:age:diabetes      1   102.599 23622 2289.1
## - glucose:pressure:mass:pedigree:age:diabetes      1   125.875 23645 2289.6
## 
## Step:  AIC=2287.57
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:glucose:pressure:pedigree:age + 
##     pregnant:glucose:mass:pedigree:age + pregnant:pressure:mass:pedigree:age + 
##     glucose:pressure:mass:pedigree:age + pregnant:glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:pressure:mass:pedigree:diabetes + glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:mass:age:diabetes + 
##     pregnant:pressure:mass:age:diabetes + glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + pregnant:pressure:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes + 
##     glucose:mass:pedigree:age:diabetes + pressure:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:mass:pedigree:age:diabetes + 
##     pregnant:pressure:mass:pedigree:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                                Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pressure:pedigree:age        1     23.42 23579 2286.1
## - pregnant:pressure:mass:pedigree:age:diabetes  1     43.71 23599 2286.6
## <none>                                                      23555 2287.6
## - pregnant:glucose:mass:pedigree:age:diabetes   1     88.49 23644 2287.6
## - pregnant:glucose:pressure:mass:age:diabetes   1     93.39 23649 2287.7
## - glucose:pressure:mass:pedigree:age:diabetes   1    126.11 23681 2288.4
## - pregnant:glucose:pressure:pedigree:diabetes   1    392.82 23948 2294.5
## 
## Step:  AIC=2286.1
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + pregnant:pressure:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                                Df Sum of Sq   RSS    AIC
## - pregnant:pressure:mass:pedigree:age:diabetes  1     57.31 23636 2285.4
## - pregnant:glucose:mass:pedigree:age:diabetes   1     77.11 23656 2285.9
## - pregnant:glucose:pressure:mass:age:diabetes   1     83.98 23663 2286.0
## <none>                                                      23579 2286.1
## - glucose:pressure:mass:pedigree:age:diabetes   1    153.43 23732 2287.6
## - pregnant:glucose:pressure:pedigree:diabetes   1    467.48 24046 2294.7
## 
## Step:  AIC=2285.42
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     pregnant:pressure:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:mass:pedigree:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:pressure:pedigree:age:diabetes      1     29.58 23666 2284.1
## - pregnant:glucose:mass:pedigree:age:diabetes  1     50.97 23687 2284.6
## <none>                                                     23636 2285.4
## - glucose:pressure:mass:pedigree:age:diabetes  1    119.92 23756 2286.2
## - pregnant:glucose:pressure:mass:age:diabetes  1    127.11 23763 2286.3
## - pregnant:pressure:mass:pedigree:diabetes     1    209.94 23846 2288.2
## - pregnant:pressure:mass:pedigree:age          1    356.41 23993 2291.5
## - pregnant:glucose:pressure:pedigree:diabetes  1    435.83 24072 2293.3
## 
## Step:  AIC=2284.09
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes + 
##     glucose:mass:pedigree:age:diabetes + pressure:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + pregnant:glucose:mass:pedigree:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:mass:pedigree:age:diabetes  1     52.97 23719 2283.3
## <none>                                                     23666 2284.1
## - glucose:pressure:mass:pedigree:age:diabetes  1     96.88 23763 2284.3
## - pregnant:glucose:pressure:mass:age:diabetes  1    140.34 23806 2285.3
## - pregnant:pressure:mass:pedigree:diabetes     1    212.23 23878 2286.9
## - pregnant:pressure:mass:pedigree:age          1    328.12 23994 2289.5
## - pregnant:glucose:pressure:pedigree:diabetes  1    410.46 24076 2291.4
## 
## Step:  AIC=2283.3
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:glucose:mass:pedigree:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + pregnant:glucose:pedigree:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes + 
##     glucose:mass:pedigree:age:diabetes + pressure:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:mass:pedigree:age           1     30.02 23749 2282.0
## - pregnant:mass:pedigree:age:diabetes          1     37.22 23756 2282.2
## - pregnant:glucose:pedigree:age:diabetes       1     58.64 23777 2282.6
## <none>                                                     23719 2283.3
## - glucose:pressure:mass:pedigree:age:diabetes  1    100.55 23819 2283.6
## - pregnant:glucose:pressure:mass:age:diabetes  1    151.49 23870 2284.8
## - pregnant:glucose:mass:pedigree:diabetes      1    162.55 23881 2285.0
## - pregnant:pressure:mass:pedigree:diabetes     1    188.01 23907 2285.6
## - pregnant:pressure:mass:pedigree:age          1    279.08 23998 2287.6
## - pregnant:glucose:pressure:pedigree:diabetes  1    415.64 24134 2290.7
## 
## Step:  AIC=2281.99
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:pressure:mass:pedigree:age + 
##     glucose:pressure:mass:pedigree:age + pregnant:glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:pressure:mass:pedigree:diabetes + glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:mass:age:diabetes + 
##     pregnant:pressure:mass:age:diabetes + glucose:pressure:mass:age:diabetes + 
##     pregnant:glucose:pedigree:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pedigree:age:diabetes       1     58.24 23807 2281.3
## - pregnant:mass:pedigree:age:diabetes          1     82.52 23831 2281.9
## <none>                                                     23749 2282.0
## - glucose:pressure:mass:pedigree:age:diabetes  1     98.40 23847 2282.2
## - pregnant:pressure:mass:pedigree:diabetes     1    167.24 23916 2283.8
## - pregnant:glucose:mass:pedigree:diabetes      1    169.54 23918 2283.8
## - pregnant:glucose:pressure:mass:age:diabetes  1    199.24 23948 2284.5
## - pregnant:pressure:mass:pedigree:age          1    258.31 24007 2285.8
## - pregnant:glucose:pressure:pedigree:diabetes  1    431.64 24180 2289.7
## 
## Step:  AIC=2281.31
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:glucose:pedigree:age + pregnant:pressure:pedigree:age + 
##     glucose:pressure:pedigree:age + pregnant:mass:pedigree:age + 
##     glucose:mass:pedigree:age + pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:diabetes + pregnant:glucose:mass:diabetes + 
##     pregnant:pressure:mass:diabetes + glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pedigree:diabetes + pregnant:pressure:pedigree:diabetes + 
##     glucose:pressure:pedigree:diabetes + pregnant:mass:pedigree:diabetes + 
##     glucose:mass:pedigree:diabetes + pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:age:diabetes + pregnant:pressure:age:diabetes + 
##     glucose:pressure:age:diabetes + pregnant:mass:age:diabetes + 
##     glucose:mass:age:diabetes + pressure:mass:age:diabetes + 
##     pregnant:pedigree:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:pressure:mass:pedigree:age + 
##     glucose:pressure:mass:pedigree:age + pregnant:glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:pressure:mass:pedigree:diabetes + glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:mass:age:diabetes + 
##     pregnant:pressure:mass:age:diabetes + glucose:pressure:mass:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + pregnant:mass:pedigree:age:diabetes + 
##     glucose:mass:pedigree:age:diabetes + pressure:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:glucose:pedigree:age                1      0.62 23808 2279.3
## - pregnant:mass:pedigree:age:diabetes          1     67.31 23874 2280.8
## <none>                                                     23807 2281.3
## - glucose:pressure:mass:pedigree:age:diabetes  1    127.93 23935 2282.2
## - pregnant:glucose:mass:pedigree:diabetes      1    137.92 23945 2282.4
## - pregnant:pressure:mass:pedigree:diabetes     1    164.23 23971 2283.0
## - pregnant:glucose:pressure:mass:age:diabetes  1    182.03 23989 2283.4
## - pregnant:pressure:mass:pedigree:age          1    245.02 24052 2284.8
## - pregnant:glucose:pressure:pedigree:diabetes  1    374.14 24181 2287.8
## 
## Step:  AIC=2279.33
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pressure:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:mass:diabetes + pregnant:pressure:mass:diabetes + 
##     glucose:pressure:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pressure:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:mass:age:diabetes + glucose:mass:age:diabetes + 
##     pressure:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     pregnant:mass:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:mass:pedigree:age:diabetes          1     66.75 23874 2278.8
## <none>                                                     23808 2279.3
## - glucose:pressure:mass:pedigree:age:diabetes  1    129.21 23937 2280.2
## - pregnant:glucose:mass:pedigree:diabetes      1    141.45 23949 2280.5
## - pregnant:pressure:mass:pedigree:diabetes     1    166.12 23974 2281.1
## - pregnant:glucose:pressure:mass:age:diabetes  1    181.78 23989 2281.4
## - pregnant:pressure:mass:pedigree:age          1    253.66 24061 2283.1
## - pregnant:glucose:pressure:pedigree:diabetes  1    373.97 24182 2285.8
## 
## Step:  AIC=2278.84
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pressure:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:mass:diabetes + pregnant:pressure:mass:diabetes + 
##     glucose:pressure:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pressure:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:mass:age:diabetes + glucose:mass:age:diabetes + 
##     pressure:mass:age:diabetes + pregnant:pedigree:age:diabetes + 
##     glucose:pedigree:age:diabetes + pressure:pedigree:age:diabetes + 
##     mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age + 
##     pregnant:pressure:mass:pedigree:age + glucose:pressure:mass:pedigree:age + 
##     pregnant:glucose:pressure:mass:diabetes + pregnant:glucose:pressure:pedigree:diabetes + 
##     pregnant:glucose:mass:pedigree:diabetes + pregnant:pressure:mass:pedigree:diabetes + 
##     glucose:pressure:mass:pedigree:diabetes + pregnant:glucose:pressure:age:diabetes + 
##     pregnant:glucose:mass:age:diabetes + pregnant:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:age:diabetes + glucose:pressure:pedigree:age:diabetes + 
##     glucose:mass:pedigree:age:diabetes + pressure:mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age:diabetes + glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## - pregnant:pedigree:age:diabetes               1      4.16 23878 2276.9
## <none>                                                     23874 2278.8
## - glucose:pressure:mass:pedigree:age:diabetes  1    120.38 23995 2279.6
## - pregnant:glucose:mass:pedigree:diabetes      1    132.49 24007 2279.8
## - pregnant:pressure:mass:pedigree:diabetes     1    148.04 24022 2280.2
## - pregnant:glucose:pressure:mass:age:diabetes  1    179.09 24053 2280.9
## - pregnant:pressure:mass:pedigree:age          1    206.51 24081 2281.5
## - pregnant:glucose:pressure:pedigree:diabetes  1    373.88 24248 2285.2
## 
## Step:  AIC=2276.93
## triceps ~ pregnant + glucose + pressure + mass + pedigree + age + 
##     diabetes + pregnant:glucose + pregnant:pressure + glucose:pressure + 
##     pregnant:mass + glucose:mass + pressure:mass + pregnant:pedigree + 
##     glucose:pedigree + pressure:pedigree + mass:pedigree + pregnant:age + 
##     glucose:age + pressure:age + mass:age + pedigree:age + pregnant:diabetes + 
##     glucose:diabetes + pressure:diabetes + mass:diabetes + pedigree:diabetes + 
##     age:diabetes + pregnant:glucose:pressure + pregnant:glucose:mass + 
##     pregnant:pressure:mass + glucose:pressure:mass + pregnant:glucose:pedigree + 
##     pregnant:pressure:pedigree + glucose:pressure:pedigree + 
##     pregnant:mass:pedigree + glucose:mass:pedigree + pressure:mass:pedigree + 
##     pregnant:glucose:age + pregnant:pressure:age + glucose:pressure:age + 
##     pregnant:mass:age + glucose:mass:age + pressure:mass:age + 
##     pregnant:pedigree:age + glucose:pedigree:age + pressure:pedigree:age + 
##     mass:pedigree:age + pregnant:glucose:diabetes + pregnant:pressure:diabetes + 
##     glucose:pressure:diabetes + pregnant:mass:diabetes + glucose:mass:diabetes + 
##     pressure:mass:diabetes + pregnant:pedigree:diabetes + glucose:pedigree:diabetes + 
##     pressure:pedigree:diabetes + mass:pedigree:diabetes + pregnant:age:diabetes + 
##     glucose:age:diabetes + pressure:age:diabetes + mass:age:diabetes + 
##     pedigree:age:diabetes + pregnant:glucose:pressure:mass + 
##     pregnant:glucose:pressure:pedigree + pregnant:glucose:mass:pedigree + 
##     pregnant:pressure:mass:pedigree + glucose:pressure:mass:pedigree + 
##     pregnant:glucose:pressure:age + pregnant:glucose:mass:age + 
##     pregnant:pressure:mass:age + glucose:pressure:mass:age + 
##     pregnant:pressure:pedigree:age + glucose:pressure:pedigree:age + 
##     pregnant:mass:pedigree:age + glucose:mass:pedigree:age + 
##     pressure:mass:pedigree:age + pregnant:glucose:pressure:diabetes + 
##     pregnant:glucose:mass:diabetes + pregnant:pressure:mass:diabetes + 
##     glucose:pressure:mass:diabetes + pregnant:glucose:pedigree:diabetes + 
##     pregnant:pressure:pedigree:diabetes + glucose:pressure:pedigree:diabetes + 
##     pregnant:mass:pedigree:diabetes + glucose:mass:pedigree:diabetes + 
##     pressure:mass:pedigree:diabetes + pregnant:glucose:age:diabetes + 
##     pregnant:pressure:age:diabetes + glucose:pressure:age:diabetes + 
##     pregnant:mass:age:diabetes + glucose:mass:age:diabetes + 
##     pressure:mass:age:diabetes + glucose:pedigree:age:diabetes + 
##     pressure:pedigree:age:diabetes + mass:pedigree:age:diabetes + 
##     pregnant:glucose:pressure:mass:age + pregnant:pressure:mass:pedigree:age + 
##     glucose:pressure:mass:pedigree:age + pregnant:glucose:pressure:mass:diabetes + 
##     pregnant:glucose:pressure:pedigree:diabetes + pregnant:glucose:mass:pedigree:diabetes + 
##     pregnant:pressure:mass:pedigree:diabetes + glucose:pressure:mass:pedigree:diabetes + 
##     pregnant:glucose:pressure:age:diabetes + pregnant:glucose:mass:age:diabetes + 
##     pregnant:pressure:mass:age:diabetes + glucose:pressure:mass:age:diabetes + 
##     glucose:pressure:pedigree:age:diabetes + glucose:mass:pedigree:age:diabetes + 
##     pressure:mass:pedigree:age:diabetes + pregnant:glucose:pressure:mass:age:diabetes + 
##     glucose:pressure:mass:pedigree:age:diabetes
## 
##                                               Df Sum of Sq   RSS    AIC
## <none>                                                     23878 2276.9
## - glucose:pressure:mass:pedigree:age:diabetes  1    125.61 24004 2277.8
## - pregnant:glucose:mass:pedigree:diabetes      1    134.62 24013 2278.0
## - pregnant:pressure:mass:pedigree:diabetes     1    156.76 24035 2278.5
## - pregnant:glucose:pressure:mass:age:diabetes  1    177.98 24056 2278.9
## - pregnant:pressure:mass:pedigree:age          1    203.69 24082 2279.5
## - pregnant:glucose:pressure:pedigree:diabetes  1    370.87 24249 2283.3

Insulin

Nell’ultimo caso basta fare un unico modello. OOra tutti gli NA sono stati corretti.

varDip = "insulin"
colonne = names(df)[names(df) != varDip]
modMass = MASS::stepAIC(lm(as.formula(paste(varDip," ~ ",paste(colonne,collapse = " * "))), data = df))
## Start:  AIC=3339.49
## insulin ~ pregnant * glucose * pressure * triceps * mass * pedigree * 
##     age * diabetes
## 
##                                                                Df Sum of Sq
## <none>                                                                     
## - pregnant:glucose:pressure:triceps:mass:pedigree:age:diabetes  1     12159
##                                                                   RSS    AIC
## <none>                                                         515410 3339.5
## - pregnant:glucose:pressure:triceps:mass:pedigree:age:diabetes 527570 3346.7
righe = is.na(df[,varDip])

df[righe,varDip] = predict(modMass, newdata = df[righe,])

anyNA.data.frame(df)
## [1] FALSE

Modello glm

Il modello senza le modifiche sugli NA è il seguente:

modGlmNA = glm(diabetes ~ ., family = binomial, data = PimaIndiansDiabetes2)
summary(modGlmNA)
## 
## Call:
## glm(formula = diabetes ~ ., family = binomial, data = PimaIndiansDiabetes2)
## 
## Deviance Residuals: 
##     Min       1Q   Median       3Q      Max  
## -2.7823  -0.6603  -0.3642   0.6409   2.5612  
## 
## Coefficients:
##               Estimate Std. Error z value Pr(>|z|)    
## (Intercept) -1.004e+01  1.218e+00  -8.246  < 2e-16 ***
## pregnant     8.216e-02  5.543e-02   1.482  0.13825    
## glucose      3.827e-02  5.768e-03   6.635 3.24e-11 ***
## pressure    -1.420e-03  1.183e-02  -0.120  0.90446    
## triceps      1.122e-02  1.708e-02   0.657  0.51128    
## insulin     -8.253e-04  1.306e-03  -0.632  0.52757    
## mass         7.054e-02  2.734e-02   2.580  0.00989 ** 
## pedigree     1.141e+00  4.274e-01   2.669  0.00760 ** 
## age          3.395e-02  1.838e-02   1.847  0.06474 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 498.10  on 391  degrees of freedom
## Residual deviance: 344.02  on 383  degrees of freedom
##   (376 osservazioni eliminate a causa di valori mancanti)
## AIC: 362.02
## 
## Number of Fisher Scoring iterations: 5

Il seguente modello, invece, è stato prodotto con le modifichesugli NA:

modGlm = glm(diabetes ~ ., family = binomial, data = df)
summary(modGlm)
## 
## Call:
## glm(formula = diabetes ~ ., family = binomial, data = df)
## 
## Deviance Residuals: 
##     Min       1Q   Median       3Q      Max  
## -2.8630  -0.7002  -0.3947   0.7050   2.4617  
## 
## Coefficients:
##               Estimate Std. Error z value Pr(>|z|)    
## (Intercept) -9.382e+00  8.289e-01 -11.319  < 2e-16 ***
## pregnant     1.339e-01  3.303e-02   4.054 5.04e-05 ***
## glucose      3.755e-02  3.653e-03  10.279  < 2e-16 ***
## pressure    -8.373e-03  8.686e-03  -0.964  0.33506    
## triceps     -2.265e-02  8.778e-03  -2.581  0.00986 ** 
## insulin      8.522e-06  2.141e-05   0.398  0.69067    
## mass         1.172e-01  1.802e-02   6.505 7.77e-11 ***
## pedigree     9.837e-01  3.005e-01   3.274  0.00106 ** 
## age          1.291e-02  9.611e-03   1.344  0.17903    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 993.48  on 767  degrees of freedom
## Residual deviance: 703.75  on 759  degrees of freedom
## AIC: 721.75
## 
## Number of Fisher Scoring iterations: 5

Fare un confronto sui due modelli tramite AIC non è opportuno in quanto sono stati utilizzati due dataset diversi, metodi migliori per testare i due modelli sono set validation, cross validation, …

# LOO-CV
cv = boot::cv.glm(df, modGlm, K = nrow(df))
cvNA = boot::cv.glm(na.omit(PimaIndiansDiabetes2), modGlmNA)
data.frame("NA sistemati" = cv$delta,
           "Dati grezzi" = cvNA$delta)

Secondo la cross validazione, metodo leave one out, il modello da scegliere è quello senza NA. Nel caso in cui sia presente un’osservazione con NA non sarà applicabile il modello, a meno che non venga fatto il “riempimento” degli NA, come fatto in precedenza.

Costruire curva ROC

# modifico l'ordine dei livelli della variabile fattoriale
df$diabetes = relevel(df$diabetes,"pos")

set.seed(1)
train = sample(1:nrow(df), .8 * nrow(df))
modGlmTrain = glm(diabetes ~ ., 
                  family = binomial, 
                  data = df,
                  subset = train)

pred = predict(modGlmTrain, df[-train,], type = "response")

curvaROC = function(pred, oss, dettaglio = 100)
{
  tpr = c(0)
  fpr = c(0)
  for(i in 1:(dettaglio - 1))
  {
    previsto = factor(ifelse(pred < (i/dettaglio), "pos", "neg"),
                      levels = c("pos","neg"),
                      labels = c("pos","neg"),
                      ordered = T)
    t = table(oss,previsto)
    # sono invertiti perché  nella tabella mi metteva prima i negativi e poii i positivi, in alternativa era da cambiare l'ordine dei livelli della variabile fattoriale
    if(length(t) == 4)
    {
      tpr = c(tpr, (t[1] / (t[1] + t[3]))) 
      fpr = c(fpr, (t[2] / (t[2] + t[4])))
    }else
    {
      tpr = c(tpr, 1)
      fpr = c(fpr, (t[1] / (t[2] + t[1])))
    }
  }
  tpr = c(tpr, 1)
  fpr = c(fpr, 1)
  return(data.frame(tpr,fpr))
}

plotROC = function(dfROC)
{
  ggplot(dfROC, aes(x = fpr, y = tpr)) +
    geom_line(color = "blue") +
    geom_line(aes(x = x, y = x),
              data = data.frame(x = c(0,1)), # non è stato utilizzato abline per limitare la linea tra 0 e 1
              color = "red") +
    labs(x = "False Positive Rate",
         y = "True Positive Rate",
         title = "Curva ROC")
}
# maggiore è il dettaglio, più la funzione sarà a scalino, minore arà la variabile dettaglio, la curva sarà più liscia (smoothies)
plotROC(curvaROC(pred, df$diabetes[-train], dettaglio = 20))

Calcolare AUC

L’AUC del modello si attesta al 87%, si può affermare che è un buon modello.

calcoloAUC = function(dfROC)
  return(sum(sapply(1:(length(dfROC$tpr) - 1),
                    function(i) dfROC$tpr[i + 1] * (dfROC$fpr[i+1]-dfROC$fpr[i]))))


calcoloAUC(curvaROC(pred, df$diabetes[-train], 500))
## [1] 0.8749286

Esercizio 2

Regressione logistica semiparametrica

Di seguito un modello di regressione logistica semiparametrica, al cui interno sono state inserite spline cubiche e una polinomiale di secondo grado.

modGlmSP = gam(diabetes ~ bs(triceps) + bs(insulin) + poly(age,degree = 2) + glucose + bs(mass) + bs(pedigree),
               family = binomial,
               data = df,
               subset = train)
summary(modGlmSP)
## 
## Family: binomial 
## Link function: logit 
## 
## Formula:
## diabetes ~ bs(triceps) + bs(insulin) + poly(age, degree = 2) + 
##     glucose + bs(mass) + bs(pedigree)
## 
## Parametric coefficients:
##                          Estimate Std. Error z value Pr(>|z|)    
## (Intercept)            -2.503e+00  5.365e+00  -0.467  0.64081    
## bs(triceps)1            1.696e+01  8.661e+00   1.959  0.05015 .  
## bs(triceps)2           -7.754e+01  2.667e+01  -2.908  0.00364 ** 
## bs(triceps)3            2.621e+02  8.605e+01   3.046  0.00232 ** 
## bs(insulin)1            5.903e+01  2.206e+01   2.676  0.00746 ** 
## bs(insulin)2           -1.026e+02  3.674e+01  -2.793  0.00522 ** 
## bs(insulin)3           -2.410e+02  8.320e+01  -2.897  0.00377 ** 
## poly(age, degree = 2)1 -9.401e+00  3.364e+00  -2.794  0.00520 ** 
## poly(age, degree = 2)2  1.684e+01  3.571e+00   4.715 2.42e-06 ***
## glucose                -3.568e-02  4.206e-03  -8.484  < 2e-16 ***
## bs(mass)1              -1.028e+01  3.440e+00  -2.989  0.00280 ** 
## bs(mass)2               3.761e+00  2.829e+00   1.330  0.18366    
## bs(mass)3              -1.492e+01  5.308e+00  -2.810  0.00495 ** 
## bs(pedigree)1          -7.919e-01  1.431e+00  -0.554  0.57989    
## bs(pedigree)2          -2.959e+00  1.880e+00  -1.574  0.11555    
## bs(pedigree)3           7.809e-01  1.734e+00   0.450  0.65250    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## R-sq.(adj) =  0.376   Deviance explained = 34.2%
## UBRE = -0.093437  Scale est. = 1         n = 614

Un modello alternativo che considera le interazioni ma perde l’interpretabilità è il seguente. Dal punto di vista computazionale è molto pesante da elaborare, quindi non viene eseguito.

varEsp = names(df)[names(df) != "diabetes"]
splineCubiche = paste("bs(",varEsp, ")", sep = "", collapse = " + ")
interazione = paste("ti(", paste(varEsp, collapse = ", "), ")", sep = "")
formula = as.formula(paste("diabetes ~", splineCubiche, "+", interazione))
# modGlmSPInterazioni = gam(formula, family = binomial, data = df)
# summary(modGlmSPInterazioni)

Albero di classificazione

set.seed(1)
modTree = rpart(diabetes ~ ., 
                data = df,
                subset = train,
                method = "class",
                control = rpart.control(minsplit = 5, cp = 0.00001))
plot(modTree)

Potatura

{
  plotcp(modTree)
  points(x = which.min(modTree$cptable[,"xerror"]),
         y = min(modTree$cptable[,"xerror"]),
         col = "red",
         pch = 18)
}

modTree = prune(modTree, 
                cp = modTree$cptable[which.min(modTree$cptable[,"xerror"]),"CP"])
rpart.plot(modTree, cex = .65)

Confronto

Accuratezza

predGlm = factor(ifelse(predict(modGlmSP, newdata = df[-train,], type = "response") > .5, "pos", "neg"))
matConfGlm = confusionMatrix(predGlm, df$diabetes[-train])

predTree = factor(predict(modTree, newdata = df[-train,], type = "class"))
matConfTree = confusionMatrix(predTree, df$diabetes[-train])

data.frame("Regressione lineare" = round(matConfGlm$overall,3),
           "Albero di classificazione" = round(matConfTree$overall,3))

Curva ROC

Modello di regressione logistica semiparemtirca

plotROC(curvaROC(predict(modGlmSP, newdata = df[-train,], type = "response"),
                 df$diabetes[-train]))

Albero di classificazione

plotROC(curvaROC(predict(modTree, newdata = df[-train,], type = "prob")[,2],
                 df$diabetes[-train]))

Esercizio 3

Importo i dati

data("iris")
str(iris)
## 'data.frame':    150 obs. of  5 variables:
##  $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
##  $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
##  $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
##  $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
##  $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...

Albero di classificazione

L’albero di classificazione risulta essere con pochi nodi e quasi tutti i nodi terminali hanno solo classificazioni corrette. Questo fa pensare che le specie tra loro siano molto diverse, ovvero che la varianza tra le specie sia decisamente maggiore che la varianza nelle specie.

# campionamento
set.seed(1)
train = sample(1:nrow(iris), .7 * nrow(iris))

# growing
modTree = rpart(Species ~ ., 
                data = iris,
                subset = train,
                method = "class",
                control = rpart.control(minsplit = 5, cp = 0.00001))

# potatura
modTree = prune(modTree, 
                cp = modTree$cptable[which.min(modTree$cptable[,"xerror"]),"CP"])
rpart.plot(modTree, cex = .8)

Matrice di confusione

L’acccuratezza risulta molto elevata, anche se si intuiva già dal grafico soprastante. Durante il test solo una pianta è stata classificata erroneamente, questo porterà degli ottimi risultati per la specificità e la sensibilità delle varie classi che saranno quasi tutte uguali a 1.

predTree = factor(predict(modTree, newdata = iris[-train,], type = "class"))
matConfTree = confusionMatrix(predTree, iris$Species[-train])
cvms::plot_confusion_matrix(cvms::confusion_matrix(targets = iris$Species[-train],
                                                   predictions = predict(modTree, 
                                                                         newdata = iris[-train,],
                                                                         type = "class"))$`Confusion Matrix`[[1]])