Page 361 - Applied Statistics with R

14.2. PREDICTOR TRANSFORMATION 361

0.6

3.5 0.4
0.2
log(mpg) 3.0 Residuals 0.0

-0.2
2.5 -0.4
-0.6

4.0 4.5 5.0 5.5 2.4 2.6 2.8 3.0 3.2 3.4 3.6
log(hp) Fitted

big_model = lm(mpg ~ disp * hp * domestic, data = autompg)

qqnorm(resid(big_model), col = "darkgrey")
qqline(resid(big_model), col = "dodgerblue", lwd = 2)

Normal Q-Q Plot

15 10
Sample Quantiles 5 0

-10 -5

-3 -2 -1 0 1 2 3

Theoretical Quantiles

bigger_model = lm(log(mpg) ~ disp * hp * domestic +
I(disp ^ 2) + I(hp ^ 2), data = autompg)
summary(bigger_model)