Answer Happy

Consider the classification trees in Figures 5.11(a) and (b). a. Use the mortgage default tree in Figure 5.11(a) to estimate the percentage of all mortgage applicants with a household income of $65,000 and debt of $20,000 who would default. Percentage of default applicants % b. Salford Systems (see Salford-systems.com) describes a study it helped carry out at UC San Diego to predict the probability that a heart attack survivor would have a second heart attack within 30 days. The study measured the values of over 100 variables concerning demographics, medical history, and lab results for heart attack survivors. From Salford Systems' description of the results, we have constructed the second heart attack tree in Figure 5.11(b). Use the tree to estimate the percentage of all 65-year-old heart attack survivors with a systolic blood pressure of 120 and with no sinus tachycardia who would have a second heart attack within 30 days. Salford Systems reports that the second heart attack tree has helped doctors tremendously in developing successful treatment plans for heart attack survivors. Percentage of heart attack survivors %

(a) Mortgage default tree No 0.10 0 0 1 1 1 1 (c) The coupon redemption data CoupRedemp Coupon Purchases Card 0 10.52 0 14.89 15.75 29.27 48.15 51.40 29.89 0 0 0 1 1 1 0 1 0 0 1 0 1 1 0 0 1 0 0 0 1 1 1 Household income > $50,000? No On Job >5 yr? 0 1 1 0 0 0 0 21.23 17.55 46.61 28.01 15.97 50.10 51.62 27.48 4.95 43.25 35.04 28.94 53.67 13.24 51.54 42.05 29.71 39.24 58.38 23.75 23.89 50.94 36.37 34.40 38.01 55.87 21.46 40.75 46.52 34.93 31.97 0.05 42.28 26.28 0 1 1 1 0 1 0 1 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 0 1 0 0 0 Yes No 1 1 1 0 1 1 0 0 0 0 Yes Debt> $15,000? 0.01 Count 0 1 PE Purchases>=36.37 12 Level 0 1 0.04 Count G2 LogWorth 20 20.016097 16007719 Level Rate Prob Count 0.2000 0.2167 4 0.8000 0.7833 16 Yes Card(1) 0.0000 0.0397 1.0000 0.9603 G^2 0 Rate Prob Count (d) JMP output of a classification tree for the coupon redemption data (for Exercise 5.3) (b) Second heart attack tree Systolic Blood Pressure <91? Count Yes .70 RSquare 0.644 N 40 Purchases<36.37 All Rows Yes .02 G^2 8 11090355 Level Rate Prob Count 0 0 0.5000 0.5019 12 1 0.5000 0.4981 4 Count G2 LogWorth 40 55.051105 5.5715641 Number of Splits 3 Level Rate Prob Count 0 0.5500 0.5500 1 0.4500 0.4500 Count 22 18 No Age <62.5? 0 1 Yes .50 Sinus Tachycardia? Purchases>=42.28 Count G2 LogWorth 20 13.003319 0.9797146 Level Rate Prob Count 0.9000 0.8833 0.1000 0.1167 No Cardio 30 21 18 2 No Purchases<42.28 .11 G^2 Count G^2 5 6.7301167 15 0 Level Rate Prob Count Level Rate Prob Count 0 0.6000 0.5972 1.0000 0.9740 0.0000 0.0260 1 0.4000 0.4028 15 0