Consider the following set of data:

y x1 x2 x3 x4 61 37 18 2 13 37 25 5 4 10 22 23 12 7 4 48 12 6 2 15 66 34 14 3 25 y x1 x2 x3 x4 69 35 21 2 20 24 23 7 6 9 68 35 15 3 14 65 37 19 2 19 45 30 12 3 12

a. Use standard stepwise regression to produce an estimate of a multiple regression model to predict y.

b. Use forward selection stepwise regression to produce an estimate of a multiple regression model to predict y.

c. Use backwards elimination stepwise regression to produce an estimate of a multiple regression model to predict y.

d. Use best subsets regression to produce an estimate of a multiple regression model to predict y.