A group of 24 stroke patients is randomly split into a treat

A group of 24 stroke patients is randomly split into a treatment group and a control group. The treatment group receives aerobic exercise, while the control group does not. The V02 (a measure of fitness, in mL/kg/min) of each patient in both groups is measured before and after the treatment. The changes in V02 (after minus before, positive is good) for the treatment group are -2.3, -0.7, -0.2,0.1,0.5,0.8,0.9,1.6,2.0,3.9,4.5,6.0 while the changes for the control group are -2.9, -1.5, -0.9. -0.8, -0.7, -0.5, -0.2,0.2,0.6,1.2,1.9,2.8. What test would you use to test this hypothesis? What are the assumptions of this test? Perform a one-tailed test of the kind you named in part (a), at level 0.05. A doctor, who does not know statistics, wishes to know

Solution

a) since we need to compare the avrage change, we use t test.

the assumptions made here are

the parent population is normal

the sample size is <30.

The varinces are equal.

b)

Here we test

H0: mean1=mean2

H1: mean1>mean2

p value is less than 0.05, so we reject the null hypothesis.

C) the analysis proves that aerobic exercise does help in fitness.

Hypothesis Test: Independent Groups (t-test, pooled variance)
	Group 1	Group 2
	1.425	-0.067	mean
	2.358	1.541	std. dev.
	12	12	n
		22	df
		1.4917	difference (Group 1 - Group 2)
		3.9686	pooled variance
		1.9921	pooled std. dev.
		0.8133	standard error of difference
		0	hypothesized difference
		1.83	t
		.0401	p-value (one-tailed, upper)