Question

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	Age	Blood Pressure	Smoker
12	57	152	0
24	67	163	0
13	58	155	0
56	86	177	1
28	59	196	0
51	76	189	1
18	56	155	1
31	78	120	0
37	80	135	1
15	78	98	0
22	71	152	0
36	70	173	1
15	67	135	1
48	77	209	1
15	60	199	0
36	82	119	1
8	66	166	0
34	80	125	1
3	62	117	0
37	59	207	1

b. Using the best regression procedure, how many independent variables are in the highest adjusted R ² model?

What is the value of R ²(adj)? Note: report R ²(adj) as a percentage (to 1 decimal).

Show the best regression model below (to 3 decimals, if necessary). Enter 0 if the independent variable listed below is not in your best regression model.

Rating = ______ + ________ Age + ________ Pressure + ________Smoker

Answer 1

Regression Analysis
	R²	0.873
	Adjusted R²	0.850
	R	0.935
	Std. Error	5.757
	n	20
	k	3
	Dep. Var.	Risk
ANOVA table
Source	SS	df	MS	F	p-value
Regression	3,660.7396	3	1,220.2465	36.82	2.06E-07
Residual	530.2104	16	33.1382
Total	4,190.9500	19
Regression output				confidence interval
variables	coefficients	std. error	t (df=16)	p-value	95% lower	95% upper
Intercept	-91.7595	15.22	-6.03	0.00	-124.03	-59.49
Age	1.0767	0.1660	6.488	7.49E-06	0.7249	1.4286
Blood	0.2518	0.0452	5.568	4.24E-05	0.1559	0.3477
Smoker	8.7399	3.0008	2.912	.0102	2.3784	15.1013

b. Using the best regression procedure, how many independent variables are in the highest adjusted R ² model? Independent Variable=3 (age,Blood pressure,smoker)

What is the value of R ²(adj)? Note: report R ²(adj) as a percentage (to 1 decimal).

85.0%

Show the best regression model below (to 3 decimals, if necessary). Enter 0 if the independent variable listed below is not in your best regression model.

Rating = -91.7595 + 1.0767 Age + 0.2518Pressure + 8.7399Smoker