1. Write-up, in detail, the steps taken to do the following regressions in model building. Make sure you clearly state the CRITERIA for model selection.
a) Forward selection
b) Backward selection
c) Stepwise selection
d) Mallow’s Cp selection
2. Use the HW6.txt data and your answers to question 1 on how SAS is proceeding with the model selection for question 1, parts a, b, c, and d. The provided data set has the following variables, y, x1, x2, x3, x4, x5, and x6.
43 51 30 39 61 92 45
63 64 51 54 63 73 47
71 70 68 69 76 86 48
61 63 45 47 54 84 35
81 78 56 66 71 83 47
43 55 49 44 54 49 34
58 67 42 56 66 68 35
71 75 50 55 70 66 41
72 82 72 67 71 83 31
67 61 45 47 62 80 41
64 53 53 58 58 67 34
67 60 47 39 59 74 41
69 62 57 42 55 63 25
68 83 83 45 59 77 35
77 77 54 72 79 77 46
81 90 50 72 60 54 36
74 85 64 69 79 79 63
65 60 65 75 55 80 60
65 70 46 57 75 85 46
50 58 68 54 64 78 52
50 40 33 34 43 64 33
64 61 52 62 66 80 41
53 66 52 50 63 80 37
40 37 42 58 50 57 49
63 54 42 48 66 75 33
66 77 66 63 88 76 72
78 75 58 74 80 78 49
48 57 44 45 51 83 38
85 85 71 71 77 74 55
82 82 39 59 64 78 39
