Problem 7-19 A recent 10-year study conducted by a research team at the Medical
ID: 3311782 • Letter: P
Question
Problem 7-19
A recent 10-year study conducted by a research team at the Medical School was conducted to assess how age, blood pressure, and smoking relate to the risk of strokes. Assume that the following data are from a portion of this study. Risk is interpreted as the probability (times 100) that the patient will have a stroke over the next 10-year period. For the smoking variable, define a dummy variable with 1 indicating a smoker and 0 indicating a nonsmoker.
Click on the datafile logo to reference the data.
Risk
Age Blood
Pressure
Smoker 12 57 152 No 24 67 163 No 13 58 155 No 56 86 177 Yes 28 59 196 No 51 76 189 Yes 18 56 155 Yes 31 78 120 No 37 80 135 Yes 15 78 98 No 22 71 152 No 36 70 173 Yes 15 67 135 Yes 48 77 209 Yes 15 60 199 No 36 82 119 Yes 8 66 166 No 34 80 125 Yes 3 62 117 No 37 59 207 Yes
Explanation / Answer
a)
Regression Analysis: Risk versus Age, Blood Pressure, Smoker_Yes
The regression equation is
Risk = - 91.8 + 1.08 Age + 0.252 Blood Pressure + 8.74 Smoker_Yes
b)
From the given data,
Predictor Coef SE Coef T P
Constant -91.76 15.22 -6.03 0.000
Age 1.0767 0.1660 6.49 0.000
Blood Pressure 0.25181 0.04523 5.57 0.000
Smoker_Yes 8.740 3.001 2.91 0.010
The p-value of smoker is 0.010 < alpha 0.05, so we reject H0
Thus we conclude that smoker is significant
c)
The predict value of Risk is
Risk = - 91.8 + 1.08(68) + 0.252 (175) + 8.74 (1) = 34.27
Probability = 34.27 / 100 = 0.34
d)correct answer: (iv) All of the above