2

dados <- data.frame(
  alcool = c(1, 1, 1, 1, 0, 0, 0, 0),
  cigarros = c(1, 1, 0, 0, 1, 1, 0, 0),
  maconha = c(1, 0, 1, 0, 1, 0, 1, 0),
  Freq = c(911, 538, 44, 456, 3, 43, 2, 279)
)

3

library(MASS)

glm(dados)
## 
## Call:  glm(formula = dados)
## 
## Coefficients:
## (Intercept)     cigarros      maconha         Freq  
##    0.214839    -0.212309     0.105857     0.001189  
## 
## Degrees of Freedom: 7 Total (i.e. Null);  4 Residual
## Null Deviance:       2 
## Residual Deviance: 1.035     AIC: 16.35
loglm(dados)
## Call:
## loglm(formula = dados)
## 
## Statistics:
##                  X^2 df P(> X^2)
## Likelihood Ratio   0 -2        1
## Pearson          NaN -2        1

4

tab <- xtabs(Freq ~ alcool + cigarros + maconha, data = dados)

modelo <- loglm(Freq ~ alcool + cigarros + maconha, data = tab)
summary(modelo)
## Formula:
## Freq ~ alcool + cigarros + maconha
## attr(,"variables")
## list(Freq, alcool, cigarros, maconha)
## attr(,"factors")
##          alcool cigarros maconha
## Freq          0        0       0
## alcool        1        0       0
## cigarros      0        1       0
## maconha       0        0       1
## attr(,"term.labels")
## [1] "alcool"   "cigarros" "maconha" 
## attr(,"order")
## [1] 1 1 1
## attr(,"intercept")
## [1] 1
## attr(,"response")
## [1] 1
## attr(,".Environment")
## <environment: R_GlobalEnv>
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 1286.020  4        0
## Pearson          1411.386  4        0

5

mod1 <- loglm(Freq ~ alcool + cigarros + maconha, data = tab)
mod1
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 1286.020  4        0
## Pearson          1411.386  4        0
mod1$lrt + 2 * mod1$df
## [1] 1294.02
mod2 <- loglm(Freq ~ alcool + cigarros + maconha + cigarros*maconha, data = tab)
mod2
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + cigarros * 
##     maconha, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 534.2117  3        0
## Pearson          505.5977  3        0
mod2$lrt + 2 * mod2$df
## [1] 540.2117
mod3 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*maconha, data = tab)
mod3
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     maconha, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 939.5626  3        0
## Pearson          824.1630  3        0
mod3$lrt + 2 * mod3$df
## [1] 945.5626
mod4 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*cigarros, data = tab)
mod4
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     cigarros, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 843.8266  3        0
## Pearson          704.9071  3        0
mod4$lrt + 2 * mod4$df
## [1] 849.8266
mod5 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*cigarros + alcool*maconha, data = tab)
mod5
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     cigarros + alcool * maconha, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 497.3693  2        0
## Pearson          443.7611  2        0
mod5$lrt + 2 * mod5$df
## [1] 501.3693
mod6 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*cigarros + cigarros*maconha, data = tab)
mod6
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     cigarros + cigarros * maconha, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 92.01836  2        0
## Pearson          80.81482  2        0
mod6$lrt + 2 * mod6$df
## [1] 96.01836
mod7 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*maconha + cigarros*maconha, data = tab)
mod7
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     maconha + cigarros * maconha, data = tab)
## 
## Statistics:
##                       X^2 df P(> X^2)
## Likelihood Ratio 187.7543  2        0
## Pearson          177.6149  2        0
mod7$lrt + 2 * mod7$df
## [1] 191.7543
mod8 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*cigarros + alcool*maconha + cigarros*maconha, data = tab)
mod8
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     cigarros + alcool * maconha + cigarros * maconha, data = tab)
## 
## Statistics:
##                        X^2 df  P(> X^2)
## Likelihood Ratio 0.3739859  1 0.5408396
## Pearson          0.4010998  1 0.5265218
mod8$lrt + 2 * mod8$df
## [1] 2.373986
mod9 <- loglm(Freq ~ alcool + cigarros + maconha + alcool*cigarros + alcool*maconha + cigarros*maconha + alcool*cigarros*maconha, data = tab)
mod9
## Call:
## loglm(formula = Freq ~ alcool + cigarros + maconha + alcool * 
##     cigarros + alcool * maconha + cigarros * maconha + alcool * 
##     cigarros * maconha, data = tab)
## 
## Statistics:
##                  X^2 df P(> X^2)
## Likelihood Ratio   0  0        1
## Pearson            0  0        1
mod9$lrt + 2 * mod9$df
## [1] 0
mod8$param
## $`(Intercept)`
## [1] 4.251537
## 
## $alcool
##         0         1 
## -1.503994  1.503994 
## 
## $cigarros
##          0          1 
## -0.2822777  0.2822777 
## 
## $maconha
##         0         1 
##  1.196045 -1.196045 
## 
## $alcool.cigarros
##       cigarros
## alcool          0          1
##      0  0.5136255 -0.5136255
##      1 -0.5136255  0.5136255
## 
## $alcool.maconha
##       maconha
## alcool         0         1
##      0  0.746502 -0.746502
##      1 -0.746502  0.746502
## 
## $cigarros.maconha
##         maconha
## cigarros          0          1
##        0  0.7119739 -0.7119739
##        1 -0.7119739  0.7119739

8)

obj <- glm(Freq ~ alcool + cigarros + maconha + alcool*cigarros + alcool*maconha + cigarros*maconha + alcool*cigarros*maconha, data = tab)
obj$fitted.values
##   1   2   3   4   5   6   7   8 
## 279 456  43 538   2  44   3 911