11.18. Refer to the previous exercise.

(a) Find a 95% confidence interval for the change in the mean of y for a one-unit increase in 11.19. Use software with the "house selling price" data file atthe text Website to conduct a multiple regression analysis ofy = selling price of home (dollars), xi = size of home (square feet), X2 = number of bedrooms, X3 = number of bathrooms.

(a) Use scattcrplots to display the effects of the predictors on y. Interpret, and explain how the highly discrete nature of X2 and X3 affects the plots.

(b) Report the prediction equation and interpret the estimated partial effect of size of home.

(c) Inspect the correlation matrix, and report the variable having the (i) strongest association with y, (ii) weakest association with y.

(d) Report R 2

for this model and r 2

for the simpler model using xj alone as the predictor.

Interpret.