Question

A recent 10-year study conducted by a research team at the Great Falls Medical School was conducted to assess how age, systolic 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.

Risk	Age	Systolic 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

A. What is the probability of a stroke over the next 10 years for Art Speen, a 65-year-old smoker who has a systolic blood pressure of 167? What action might the physician recommend for this patient? B. An insurance company will only sell its Select policy to people for whom the probability of a stroke in the next ten years is less than .01. If a smoker with a systolic blood pressure of 230 applies for a Select policy, under what condition will the company sell him the policy if it adheres to this standard? C. What other factors could be included in the model as independent variables? Choose the correct answer below. (I) family history of stroke    (ii) Weight/obesity (iii) Gender    (iv) All of the above

Answer 1

(a)

Predicted values for: Risk
Age	Systolic Blood Pressure	Smoker	Predicted
65	167	1	29.021

Probability = 29.021/100 = 0.29021

(b) Risk = -91.7595 + 1.0767*Age + 0.2518*Systolic Blood Pressure + 8.7399*Smoker

0.01 = -91.7595 + 1.0767*Age + 0.2518*230 + 8.7399*1

Age = 23

The company sell him the policy if his age is 23.

(c)  (iv) All of the above