In Exercise 14.3, backward elimination and forward selection choose the model with explanatory variables SIZE, BATHS, and NEW.

(a) Fit this model with the Houses2 data set. Inspect the leverages and the DFFIT and DFBETA values for SIZE.

Refit the model without the three highly influential observations.

Compare the prediction equation, standard errors, andR2 to thefit for the completedata set. Summarize the influence of the influential observations.

(b) For this model, report the VIF values. Interpret them, and indicate whether the degree of multicollinearity is severe.