Question

A physical therapist wants to determine the difference in the proportion of men and women who participate in regular sustained physical activity. What sample size should be obtained if sheshe wishes the estimate to be within threethree percentage points with 90​% ​confidence, assuming that

a) she uses the estimates of 22.7​% male and 18.1​% female from a previous​ year?

​(b) she does not use any prior​ estimates?

Answer 1

a) p1 = 0.227, p2 = 0.181

E = 0.03

For 90% confidence, z = 1.645

Hence,

Sample size required

n = 974

b) p1 = 0.5, p2 = 0.5

E = 0.03

For 90% confidence, z = 1.645

Hence,

Sample size required

n = 1504