Consider the electronic inverter data in Table B.14 . Delete observation 2 from the original data. Electrical engineering theory suggests that we should defi ne new variables as follows: y * = ln y , x x 1 1 1 * = , x x 2 2

* = , x x 3 3 1 * = , and x x 4 4

* = .

a. Find an appropriate subset regression model for these data using all possible regressions and the C p criterion.

b. Plot the residuals versus yˆ* for this model. Comment on the plots.

c. Discuss how you could compare this model to the ones built using the original response and regressors in Problem 10.27.