(a) Plot the residuals against the explanatory variable (appraised value). To makethe

Chapter 0, Problem 24.39

(choose chapter or problem)

(a) Plot the residuals against the explanatory variable (appraised value). To makethe pattern clearer, use vertical limits 200 to 200. Explain why the pattern yousee agrees with the conditions of linear relationship and constant standarddeviation needed for regression inference.(b) Make a stemplot of the residuals. The distribution has a bit of a cluster at theleft, but there are no outliers or other strong deviations from Normality thatwould prevent regression inference.(c) Next, plot the residuals against month. Explain why the pattern fits thefact that selling prices were rising rapidly. Is your prediction in Exercise 24.24likely to be too low or too high? (Comment: The margin of error for predictionincludes the effect of rising prices. Your residual plot shows that the predictioncould be improved by using month as a second explanatory variable. This ismultiple regression, using more than one explanatory variable to predict aresponse.)