40. Refer to data on stress level in Problem 37. (a) Fit the linear regression model Y = 0 + 1X1 + 3X3 + 4X4

40. Refer to data on stress level in Problem 37.

(a) Fit the linear regression model Y = β0 + β1X1 + β3X3 + β4X4 + ε

(b) Compute R2 pred for the models in Problems 37, 38, and

(a) of this question and decide, based on the value of R2 pred, which model fits the best.

756 16 Multiple Linear Regression Analysis