# A 10-year study conducted by the American Heart Association provided data on how age, blood pressure, and smoking relate to

A 10-year study conducted by the American Heart Association provided data on how age, blood pressure, and smoking relate to the risk of strokes. Data from a portion of this study follow. Risk is interpreted as the probability (times 100) that a person will have a stroke over the next 10-year period. For the smoker variable, 1 indicates a smoker and 0 indicates a nonsmoker.
Risk amp;Age amp;Blood Pressure amp;Smoker
24 amp;57 amp;152 amp;0
13 amp;67 amp;163 amp;0
56 amp;58 amp;155 amp;0
28 amp;86 amp;177 amp;1
51 amp;59 amp;196 amp;0
18 amp;76 amp;189 amp;1
31 amp;56 amp;155 amp;1
37 amp;78 amp;120 amp;0
15 amp;80 amp;135 amp;1
22 amp;78 amp;98 amp;0
36 amp;71 amp;152 amp;0
15 amp;70 amp;173 amp;1
48 amp;67 amp;135 amp;1
15 amp;77 amp;209 amp;1
36 amp;60 amp;199 amp;0
8 amp;82 amp;119 amp;1
34 amp;66 amp;166 amp;0
3 amp;80 amp;125 amp;1
37 amp;62 amp;117 amp;0
Required:
a. Develop an estimated regression equation that can be used to predict the risk of stroke given the age and blood-pressure level.
b. Consider adding two independent variables to the model developed in part (a), one for the interaction between age and blood-pressure level and the other for whether the person is a smoker. Develop an estimated regression equation using these four independent
variables.
c. At a .05 level of significance, test to see whether the addition of the interaction term and the smoker variable contribute significantly to the estimated regression equation developed in part (a).