2.157 Look at the residuals. Refer to the previous exercise. Figure 2.35 is a plot of the residuals versus year.
(a) Interpret the residual plot.
(b) Explain how this plot highlights the deviations from the least-squares regression line that you can see in Figure 2.34.
Figure 2.35 Plot of residuals versus year for an individual who receives approximately a 5% raise each year for 20 years, Exercise 2.157.