Consider the engine thrust data in Exercise 6-46. Refit the model using y* ln y as the response variable and x*3 ln x3 as the regressor (along with x4 and x5).

(a) Test for significance of regression using   0.01. Find the P-value for this test and state your conclusions.

(b) Use the t-statistic to test H0: j  0 versus H1: j 0 for each variable in the model. If   0.01, what conclusions can you draw?

(c) Plot the residuals versus and versus x*3. Comment on these plots. How do they compare with their counterparts obtained in Exercise 6-46 parts (f ) and (g)?