Consider the following set of dependent and independent variables. These data can also be found in the Excel file Prob 1544.xlsx.

y 64 43 51 49 40 42 23 37 30 27 20 x1 74 63 78 52 44 47 35 17 15 20 17 x2 22 29 20 17 13 17 8 15 10 10 7 x3 24 15 9 38 18 17 5 40 27 30 33 x4 17 30 25 29 38 30 33 39 44 41 49

a. Perform a best subsets regression and choose the most appropriate model for these data.

b. Perform a residual analysis to verify that the conditions for the model are met.

Applications AppendixLO1