The following data represent a dependent variable and four independent variables:

y x1 x2 x3 x4 y x1 x2 x3 x4 61 37 13 10 21 68 35 17 3 33 69 35 19 9 23 48 12 8 8 30 37 25 7 11 32 65 37 11 17 19 24 23 14 7 31 66 34 15 2 33 22 23 6 7 18 45 30 9 24 31

a. Use the standard stepwise regression to produce an estimate of a multiple regression model to predict y.
Use 0.15 as the alpha to enter and to remove.

b. Change the alpha to enter to 0.01. Repeat the standard stepwise procedure.

c. Change the alpha to remove to 0.35, leaving alpha to enter to be 0.15. Repeat the standard stepwise procedure.

d. Change the alpha to remove to 0.15, leaving alpha to enter to be 0.05. Repeat the standard stepwise procedure.

e. Change the alpha to remove and to enter to 0.35.
Repeat the standard stepwise procedure.

f. Compare the estimated regression equations developed in parts a-e.