Instalando pacote

#install.packages("wooldridge")
require(wooldridge)
## Loading required package: wooldridge
require(tidyverse)
## Loading required package: tidyverse
## -- Attaching packages --------------------------------------------------------------------------------- tidyverse 1.3.0 --
## v ggplot2 3.3.2     v purrr   0.3.4
## v tibble  3.0.3     v dplyr   1.0.2
## v tidyr   1.1.2     v stringr 1.4.0
## v readr   1.3.1     v forcats 0.5.0
## -- Conflicts ------------------------------------------------------------------------------------ tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()

#Dados de fertilidade - página 324 Modelo 1: ajuste do modelo estático

data(fertil3)
dados = fertil3 %>%
        mutate(ww2 = factor(ww2),pill = factor(pill))
model1 = lm(gfr ~ pe + ww2 + pill,data=dados)
model1
## 
## Call:
## lm(formula = gfr ~ pe + ww2 + pill, data = dados)
## 
## Coefficients:
## (Intercept)           pe         ww21        pill1  
##    98.68176      0.08254    -24.23840    -31.59403
summary(model1)
## 
## Call:
## lm(formula = gfr ~ pe + ww2 + pill, data = dados)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -27.0187  -9.6195   0.3393   9.4746  28.0730 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  98.68176    3.20813  30.760  < 2e-16 ***
## pe            0.08254    0.02965   2.784  0.00694 ** 
## ww21        -24.23840    7.45825  -3.250  0.00180 ** 
## pill1       -31.59403    4.08107  -7.742 6.46e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 14.69 on 68 degrees of freedom
## Multiple R-squared:  0.4734, Adjusted R-squared:  0.4502 
## F-statistic: 20.38 on 3 and 68 DF,  p-value: 1.575e-09
car::S(model1)
## Call: lm(formula = gfr ~ pe + ww2 + pill, data = dados)
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  98.68176    3.20813  30.760  < 2e-16 ***
## pe            0.08254    0.02965   2.784  0.00694 ** 
## ww21        -24.23840    7.45825  -3.250  0.00180 ** 
## pill1       -31.59403    4.08107  -7.742 6.46e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard deviation: 14.69 on 68 degrees of freedom
## Multiple R-squared: 0.4734
## F-statistic: 20.38 on 3 and 68 DF,  p-value: 1.575e-09 
##    AIC    BIC 
## 597.12 608.50
car::residualPlots(model1)

##            Test stat Pr(>|Test stat|)  
## pe            1.7964          0.07693 .
## ww2                                    
## pill                                   
## Tukey test   -0.6590          0.50987  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
car::qqPlot(model1)

## [1]  2 51
car::marginalModelPlots(model1)

car::vif(model1)
##       pe      ww2     pill 
## 1.255727 1.200148 1.179930

Modelo com Lag 2

dados = dados %>%
        select(pe,ww2,pill,gfr,year)
  
dados = dados %>%
        mutate(pe_1=lag(pe,1),pe_2=lag(pe,2))
dados
##        pe ww2 pill   gfr year   pe_1   pe_2
## 1    0.00   0    0 124.7 1913     NA     NA
## 2    0.00   0    0 126.6 1914   0.00     NA
## 3    0.00   0    0 125.0 1915   0.00   0.00
## 4    0.00   0    0 123.4 1916   0.00   0.00
## 5   19.27   0    0 121.0 1917   0.00   0.00
## 6   23.94   0    0 119.8 1918  19.27   0.00
## 7   20.07   0    0 111.2 1919  23.94  19.27
## 8   15.33   0    0 117.9 1920  20.07  23.94
## 9   34.32   0    0 119.8 1921  15.33  20.07
## 10  36.65   0    0 111.2 1922  34.32  15.33
## 11  25.83   0    0 110.5 1923  36.65  34.32
## 12  27.34   0    0 110.9 1924  25.83  36.65
## 13  22.85   0    0 106.6 1925  27.34  25.83
## 14  21.13   0    0 102.6 1926  22.85  27.34
## 15  24.61   0    0  99.8 1927  21.13  22.85
## 16  31.96   0    0  93.8 1928  24.61  21.13
## 17  27.29   0    0  89.2 1929  31.96  24.61
## 18  18.40   0    0  89.2 1930  27.29  31.96
## 19  14.91   0    0  84.6 1931  18.40  27.29
## 20  28.36   0    0  81.7 1932  14.91  18.40
## 21  31.95   0    0  76.3 1933  28.36  14.91
## 22  33.91   0    0  78.5 1934  31.95  28.36
## 23  36.98   0    0  77.2 1935  33.91  31.95
## 24  50.12   0    0  75.8 1936  36.98  33.91
## 25  42.79   0    0  77.1 1937  50.12  36.98
## 26  32.22   0    0  79.1 1938  42.79  50.12
## 27  36.53   0    0  77.6 1939  32.22  42.79
## 28  53.33   0    0  79.9 1940  36.53  32.22
## 29 102.49   1    0  83.4 1941  53.33  36.53
## 30 137.70   1    0  91.5 1942 102.49  53.33
## 31 141.20   1    0  94.3 1943 137.70 102.49
## 32 243.83   1    0  88.4 1944 141.20 137.70
## 33 238.40   1    0  85.9 1945 243.83 141.20
## 34 193.16   0    0 101.9 1946 238.40 243.83
## 35 168.90   0    0 113.3 1947 193.16 238.40
## 36 149.79   0    0 107.3 1948 168.90 193.16
## 37 147.05   0    0 107.1 1949 149.79 168.90
## 38 163.10   0    0 106.2 1950 147.05 149.79
## 39 178.14   0    0 111.5 1951 163.10 147.05
## 40 189.43   0    0 113.9 1952 178.14 163.10
## 41 186.51   0    0 115.2 1953 189.43 178.14
## 42 165.46   0    0 118.1 1954 186.51 189.43
## 43 170.57   0    0 118.5 1955 165.46 186.51
## 44 171.00   0    0 121.2 1956 170.57 165.46
## 45 165.12   0    0 122.9 1957 171.00 170.57
## 46 158.66   0    0 120.2 1958 165.12 171.00
## 47 162.19   0    0 118.8 1959 158.66 165.12
## 48 158.28   0    0 118.0 1960 162.19 158.66
## 49 160.71   0    0 117.2 1961 158.28 162.19
## 50 161.58   0    0 112.2 1962 160.71 158.28
## 51 161.61   0    1 108.5 1963 161.58 160.71
## 52 142.73   0    1 105.0 1964 161.61 161.58
## 53 134.60   0    1  96.6 1965 142.73 161.61
## 54 133.94   0    1  91.3 1966 134.60 142.73
## 55 133.80   0    1  87.6 1967 133.94 134.60
## 56 145.10   0    1  85.7 1968 133.80 133.94
## 57 142.62   0    1  86.5 1969 145.10 133.80
## 58 130.58   0    1  87.9 1970 142.62 145.10
## 59 132.99   0    1  81.8 1971 130.58 142.62
## 60 144.85   0    1  73.4 1972 132.99 130.58
## 61 140.87   0    1  69.2 1973 144.85 132.99
## 62 130.49   0    1  68.4 1974 140.87 144.85
## 63 122.36   0    1  66.0 1975 130.49 140.87
## 64 120.08   0    1  65.8 1976 122.36 130.49
## 65 116.11   0    1  66.8 1977 120.08 122.36
## 66 118.98   0    1  65.5 1978 116.11 120.08
## 67 132.93   0    1  67.2 1979 118.98 116.11
## 68 123.17   0    1  68.4 1980 132.93 118.98
## 69 119.31   0    1  67.4 1981 123.17 132.93
## 70 102.04   0    1  67.3 1982 119.31 123.17
## 71  92.49   0    1  65.8 1983 102.04 119.31
## 72  83.90   0    1  65.4 1984  92.49 102.04
model2 = lm(gfr ~ pe + pe_1 + pe_2 + ww2 + pill,data=dados)
model2
## 
## Call:
## lm(formula = gfr ~ pe + pe_1 + pe_2 + ww2 + pill, data = dados)
## 
## Coefficients:
## (Intercept)           pe         pe_1         pe_2         ww21        pill1  
##    95.87050      0.07267     -0.00578      0.03383    -22.12650    -31.30499
summary(model2)
## 
## Call:
## lm(formula = gfr ~ pe + pe_1 + pe_2 + ww2 + pill, data = dados)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -24.6461  -9.5409  -0.0312   8.3378  29.1295 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  95.87050    3.28196  29.211  < 2e-16 ***
## pe            0.07267    0.12553   0.579   0.5647    
## pe_1         -0.00578    0.15566  -0.037   0.9705    
## pe_2          0.03383    0.12626   0.268   0.7896    
## ww21        -22.12650   10.73197  -2.062   0.0433 *  
## pill1       -31.30499    3.98156  -7.862 5.63e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 14.27 on 64 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared:  0.4986, Adjusted R-squared:  0.4594 
## F-statistic: 12.73 on 5 and 64 DF,  p-value: 1.353e-08
car::S(model2)
## Call: lm(formula = gfr ~ pe + pe_1 + pe_2 + ww2 + pill, data = dados)
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  95.87050    3.28196  29.211  < 2e-16 ***
## pe            0.07267    0.12553   0.579   0.5647    
## pe_1         -0.00578    0.15566  -0.037   0.9705    
## pe_2          0.03383    0.12626   0.268   0.7896    
## ww21        -22.12650   10.73197  -2.062   0.0433 *  
## pill1       -31.30499    3.98156  -7.862 5.63e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard deviation: 14.27 on 64 degrees of freedom
##   (2 observations deleted due to missingness)
## Multiple R-squared: 0.4986
## F-statistic: 12.73 on 5 and 64 DF,  p-value: 1.353e-08 
##    AIC    BIC 
## 578.52 594.26
car::residualPlots(model2)

##            Test stat Pr(>|Test stat|)  
## pe            1.1992          0.23493  
## pe_1          1.4842          0.14273  
## pe_2          2.1005          0.03969 *
## ww2                                    
## pill                                   
## Tukey test   -0.9888          0.32276  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
car::qqPlot(model2)

## [1]  3 51
car::marginalModelPlots(model2)

car::vif(model2)
##        pe      pe_1      pe_2       ww2      pill 
## 22.238847 35.407682 24.092658  2.625982  1.174410

Modelo com Lag 4

dados = dados %>%
        mutate(pe_3=lag(pe,3),pe_4=lag(pe,4))
dados
##        pe ww2 pill   gfr year   pe_1   pe_2   pe_3   pe_4
## 1    0.00   0    0 124.7 1913     NA     NA     NA     NA
## 2    0.00   0    0 126.6 1914   0.00     NA     NA     NA
## 3    0.00   0    0 125.0 1915   0.00   0.00     NA     NA
## 4    0.00   0    0 123.4 1916   0.00   0.00   0.00     NA
## 5   19.27   0    0 121.0 1917   0.00   0.00   0.00   0.00
## 6   23.94   0    0 119.8 1918  19.27   0.00   0.00   0.00
## 7   20.07   0    0 111.2 1919  23.94  19.27   0.00   0.00
## 8   15.33   0    0 117.9 1920  20.07  23.94  19.27   0.00
## 9   34.32   0    0 119.8 1921  15.33  20.07  23.94  19.27
## 10  36.65   0    0 111.2 1922  34.32  15.33  20.07  23.94
## 11  25.83   0    0 110.5 1923  36.65  34.32  15.33  20.07
## 12  27.34   0    0 110.9 1924  25.83  36.65  34.32  15.33
## 13  22.85   0    0 106.6 1925  27.34  25.83  36.65  34.32
## 14  21.13   0    0 102.6 1926  22.85  27.34  25.83  36.65
## 15  24.61   0    0  99.8 1927  21.13  22.85  27.34  25.83
## 16  31.96   0    0  93.8 1928  24.61  21.13  22.85  27.34
## 17  27.29   0    0  89.2 1929  31.96  24.61  21.13  22.85
## 18  18.40   0    0  89.2 1930  27.29  31.96  24.61  21.13
## 19  14.91   0    0  84.6 1931  18.40  27.29  31.96  24.61
## 20  28.36   0    0  81.7 1932  14.91  18.40  27.29  31.96
## 21  31.95   0    0  76.3 1933  28.36  14.91  18.40  27.29
## 22  33.91   0    0  78.5 1934  31.95  28.36  14.91  18.40
## 23  36.98   0    0  77.2 1935  33.91  31.95  28.36  14.91
## 24  50.12   0    0  75.8 1936  36.98  33.91  31.95  28.36
## 25  42.79   0    0  77.1 1937  50.12  36.98  33.91  31.95
## 26  32.22   0    0  79.1 1938  42.79  50.12  36.98  33.91
## 27  36.53   0    0  77.6 1939  32.22  42.79  50.12  36.98
## 28  53.33   0    0  79.9 1940  36.53  32.22  42.79  50.12
## 29 102.49   1    0  83.4 1941  53.33  36.53  32.22  42.79
## 30 137.70   1    0  91.5 1942 102.49  53.33  36.53  32.22
## 31 141.20   1    0  94.3 1943 137.70 102.49  53.33  36.53
## 32 243.83   1    0  88.4 1944 141.20 137.70 102.49  53.33
## 33 238.40   1    0  85.9 1945 243.83 141.20 137.70 102.49
## 34 193.16   0    0 101.9 1946 238.40 243.83 141.20 137.70
## 35 168.90   0    0 113.3 1947 193.16 238.40 243.83 141.20
## 36 149.79   0    0 107.3 1948 168.90 193.16 238.40 243.83
## 37 147.05   0    0 107.1 1949 149.79 168.90 193.16 238.40
## 38 163.10   0    0 106.2 1950 147.05 149.79 168.90 193.16
## 39 178.14   0    0 111.5 1951 163.10 147.05 149.79 168.90
## 40 189.43   0    0 113.9 1952 178.14 163.10 147.05 149.79
## 41 186.51   0    0 115.2 1953 189.43 178.14 163.10 147.05
## 42 165.46   0    0 118.1 1954 186.51 189.43 178.14 163.10
## 43 170.57   0    0 118.5 1955 165.46 186.51 189.43 178.14
## 44 171.00   0    0 121.2 1956 170.57 165.46 186.51 189.43
## 45 165.12   0    0 122.9 1957 171.00 170.57 165.46 186.51
## 46 158.66   0    0 120.2 1958 165.12 171.00 170.57 165.46
## 47 162.19   0    0 118.8 1959 158.66 165.12 171.00 170.57
## 48 158.28   0    0 118.0 1960 162.19 158.66 165.12 171.00
## 49 160.71   0    0 117.2 1961 158.28 162.19 158.66 165.12
## 50 161.58   0    0 112.2 1962 160.71 158.28 162.19 158.66
## 51 161.61   0    1 108.5 1963 161.58 160.71 158.28 162.19
## 52 142.73   0    1 105.0 1964 161.61 161.58 160.71 158.28
## 53 134.60   0    1  96.6 1965 142.73 161.61 161.58 160.71
## 54 133.94   0    1  91.3 1966 134.60 142.73 161.61 161.58
## 55 133.80   0    1  87.6 1967 133.94 134.60 142.73 161.61
## 56 145.10   0    1  85.7 1968 133.80 133.94 134.60 142.73
## 57 142.62   0    1  86.5 1969 145.10 133.80 133.94 134.60
## 58 130.58   0    1  87.9 1970 142.62 145.10 133.80 133.94
## 59 132.99   0    1  81.8 1971 130.58 142.62 145.10 133.80
## 60 144.85   0    1  73.4 1972 132.99 130.58 142.62 145.10
## 61 140.87   0    1  69.2 1973 144.85 132.99 130.58 142.62
## 62 130.49   0    1  68.4 1974 140.87 144.85 132.99 130.58
## 63 122.36   0    1  66.0 1975 130.49 140.87 144.85 132.99
## 64 120.08   0    1  65.8 1976 122.36 130.49 140.87 144.85
## 65 116.11   0    1  66.8 1977 120.08 122.36 130.49 140.87
## 66 118.98   0    1  65.5 1978 116.11 120.08 122.36 130.49
## 67 132.93   0    1  67.2 1979 118.98 116.11 120.08 122.36
## 68 123.17   0    1  68.4 1980 132.93 118.98 116.11 120.08
## 69 119.31   0    1  67.4 1981 123.17 132.93 118.98 116.11
## 70 102.04   0    1  67.3 1982 119.31 123.17 132.93 118.98
## 71  92.49   0    1  65.8 1983 102.04 119.31 123.17 132.93
## 72  83.90   0    1  65.4 1984  92.49 102.04 119.31 123.17
model3 = lm(gfr ~ pe + pe_1 + pe_2 + pe_3 + pe_4 + ww2 + pill,data=dados)
model3
## 
## Call:
## lm(formula = gfr ~ pe + pe_1 + pe_2 + pe_3 + pe_4 + ww2 + pill, 
##     data = dados)
## 
## Coefficients:
## (Intercept)           pe         pe_1         pe_2         pe_3         pe_4  
##   92.501551     0.088749    -0.003977     0.007395     0.018083     0.013940  
##        ww21        pill1  
##  -21.343483   -31.081643
summary(model3)
## 
## Call:
## lm(formula = gfr ~ pe + pe_1 + pe_2 + pe_3 + pe_4 + ww2 + pill, 
##     data = dados)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -22.226  -9.528  -1.111   8.016  27.068 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  92.501551   3.325483  27.816  < 2e-16 ***
## pe            0.088749   0.126185   0.703   0.4846    
## pe_1         -0.003977   0.153111  -0.026   0.9794    
## pe_2          0.007395   0.165102   0.045   0.9644    
## pe_3          0.018083   0.153589   0.118   0.9067    
## pe_4          0.013940   0.105024   0.133   0.8948    
## ww21        -21.343483  11.540771  -1.849   0.0693 .  
## pill1       -31.081643   3.896868  -7.976 5.38e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 13.67 on 60 degrees of freedom
##   (4 observations deleted due to missingness)
## Multiple R-squared:  0.5368, Adjusted R-squared:  0.4828 
## F-statistic: 9.934 on 7 and 60 DF,  p-value: 3.633e-08
car::S(model3)
## Call: lm(formula = gfr ~ pe + pe_1 + pe_2 + pe_3 + pe_4 + ww2 + pill, data =
##          dados)
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  92.501551   3.325483  27.816  < 2e-16 ***
## pe            0.088749   0.126185   0.703   0.4846    
## pe_1         -0.003977   0.153111  -0.026   0.9794    
## pe_2          0.007395   0.165102   0.045   0.9644    
## pe_3          0.018083   0.153589   0.118   0.9067    
## pe_4          0.013940   0.105024   0.133   0.8948    
## ww21        -21.343483  11.540771  -1.849   0.0693 .  
## pill1       -31.081643   3.896868  -7.976 5.38e-11 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard deviation: 13.67 on 60 degrees of freedom
##   (4 observations deleted due to missingness)
## Multiple R-squared: 0.5368
## F-statistic: 9.934 on 7 and 60 DF,  p-value: 3.633e-08 
##    AIC    BIC 
## 558.14 578.11
car::residualPlots(model3)

##            Test stat Pr(>|Test stat|)   
## pe            0.3639         0.717198   
## pe_1          0.7943         0.430231   
## pe_2          1.7128         0.092000 . 
## pe_3          2.8742         0.005625 **
## pe_4          2.8643         0.005781 **
## ww2                                     
## pill                                    
## Tukey test   -1.0861         0.277432   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
car::qqPlot(model3)

## [1]  5 51
car::marginalModelPlots(model3)

car::vif(model3)
##        pe      pe_1      pe_2      pe_3      pe_4       ww2      pill 
## 22.613849 34.635695 41.842476 37.548372 18.143900  3.301391  1.209285

Modelo com Lag 4 - seleção dos dados

Modelo Polinomial

temp <-dados[5:nrow(dados),]
model5 <- lm(  gfr ~ poly(pe,2) +
              poly(pe_1,2)+
              poly(pe_2,2)+
              poly(pe_3,2)+
              poly(pe_4,2)+
              ww2+pill, data = temp)

car::S(model5)
## Call: lm(formula = gfr ~ poly(pe, 2) + poly(pe_1, 2) + poly(pe_2, 2) +
##          poly(pe_3, 2) + poly(pe_4, 2) + ww2 + pill, data = temp)
## 
## Coefficients:
##                Estimate Std. Error t value Pr(>|t|)    
## (Intercept)     102.157      2.747  37.183  < 2e-16 ***
## poly(pe, 2)1    140.773     94.074   1.496  0.14027    
## poly(pe, 2)2     -9.245     33.264  -0.278  0.78210    
## poly(pe_1, 2)1   -9.851    127.305  -0.077  0.93860    
## poly(pe_1, 2)2   13.973     43.752   0.319  0.75066    
## poly(pe_2, 2)1   15.881    137.743   0.115  0.90863    
## poly(pe_2, 2)2   -4.706     48.439  -0.097  0.92296    
## poly(pe_3, 2)1  -63.773    142.449  -0.448  0.65614    
## poly(pe_3, 2)2   36.482     46.596   0.783  0.43703    
## poly(pe_4, 2)1  -22.742    105.030  -0.217  0.82938    
## poly(pe_4, 2)2   37.440     32.765   1.143  0.25812    
## ww21            -31.175     13.337  -2.337  0.02309 *  
## pill1           -18.410      6.074  -3.031  0.00371 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard deviation: 13.17 on 55 degrees of freedom
## Multiple R-squared: 0.6061
## F-statistic: 7.052 on 12 and 55 DF,  p-value: 1.503e-07 
##    AIC    BIC 
## 557.12 588.19
car::residualPlots(model5)

##               Test stat Pr(>|Test stat|)   
## poly(pe, 2)                                
## poly(pe_1, 2)                              
## poly(pe_2, 2)                              
## poly(pe_3, 2)                              
## poly(pe_4, 2)                              
## ww2                                        
## pill                                       
## Tukey test      -3.1184         0.001819 **
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
car::qqPlot(model5)

## 34 36 
## 30 32
car::marginalModelPlots(model5)

car::vif(model5)
##                     GVIF Df GVIF^(1/(2*Df))
## poly(pe, 2)   187.714865  2        3.701474
## poly(pe_1, 2) 406.742037  2        4.490863
## poly(pe_2, 2) 614.076560  2        4.978008
## poly(pe_3, 2) 499.564670  2        4.727678
## poly(pe_4, 2) 166.533197  2        3.592322
## ww2             4.752806  1        2.180093
## pill            3.166911  1        1.779582

Modelo com lag 4 sendo os coeficientes de forma quadrática

https://cran.r-project.org/web/packages/matlib/vignettes/linear-equations.html

#install.packages("matlib")
#require(matlib) 
temp= fertil3 %>% 
      select(pe,ww2,pill,gfr,year)
temp= temp %>%
      mutate(x1 = pe + lag(pe,1) +   lag(pe,2) +   lag(pe,3) +   lag(pe,4),
             x2 =      lag(pe,1) + 2*lag(pe,2) + 3*lag(pe,3) +  4*lag(pe,4),
             x3 =      lag(pe,1) + 4*lag(pe,2) + 9*lag(pe,3) + 16*lag(pe,4))
temp=temp[5:nrow(temp),]
          
model6 = lm(gfr ~ x1+x2+x3,data=temp)
car::S(model6)
## Call: lm(formula = gfr ~ x1 + x2 + x3, data = temp)
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 89.83667    4.62449  19.426   <2e-16 ***
## x1          -0.02485    0.09195  -0.270    0.788    
## x2           0.07714    0.15806   0.488    0.627    
## x3          -0.02029    0.03909  -0.519    0.606    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard deviation: 19.22 on 64 degrees of freedom
## Multiple R-squared: 0.02317
## F-statistic: 0.506 on 3 and 64 DF,  p-value: 0.6795 
##    AIC    BIC 
## 600.88 611.98
car::residualPlots(model6)

##            Test stat Pr(>|Test stat|)    
## x1            9.0858        4.602e-13 ***
## x2            8.2727        1.191e-11 ***
## x3            7.6338        1.560e-10 ***
## Tukey test    2.4291          0.01514 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
car::qqPlot(model6)

## 5 6 
## 1 2
car::marginalModelPlots(model6)

car::vif(model6)
##        x1        x2        x3 
##  151.7728 1917.8454 1080.8485