1. In Example 4.2, apply the same procedure, but with K = 4, and with the included predictors under the four options being {x4, x5}, {x4}, {x5} and {x4, x5, x4*x5}, where the last model includes the product of x4 and x5.

Table 4.12 Odds ratios Odds ratio for age group k Mean St. devn Median WI 43.4 7.3 42.9 36.5 5.2 36.1 30.6 3.6 30.5 04 25.8 2.4 25.7 w5 21.7 1.6 21.7 06 18.3 1.1 18.3 07 15.4 0.9 15.4 13.0 0.9 13.0 wo 11.0 1.0 11.0