Page 278 - Applied Statistics with R

278 CHAPTER 13. MODEL DIAGNOSTICS

Normal Q-Q Plot, fit_1

3

2
Sample Quantiles 1 0

-2 -1

-3
-3 -2 -1 0 1 2 3

Theoretical Quantiles

For fit_1, we have a near perfect Q-Q plot. We would believe the errors follow
a normal distribution.

qqnorm(resid(fit_2), main = "Normal Q-Q Plot, fit_2", col = "darkgrey")
qqline(resid(fit_2), col = "dodgerblue", lwd = 2)