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 she wishes the estimate to be within three percentage points with 99​% ​confidence, assuming that ​(a) she uses the estimates of 22.6​% male and 18.1​% female from a previous​ year

A sample size of 1380 should be obtained.

Step-by-step explanation:

Minimum sample size:

The minimum sample size is of:

In which z is the critical value, related to the confidence level, E is the desired margin of error, and are the proportions.

99% confidence level

So , z is the value of Z that has a pvalue of , so .

Estimates of 22.6​% male and 18.1​% female from a previous​ year

This means that .

Within 3 percentage points, minimum sample size:

This is n for which . So

Rounding up:

A sample size of 1380 should be obtained.

13.33%

say 50 oranges, then 100 apples

80 are red, 20 are yellow

total fruit = 150

20chances out of 150 for yellow

20/150 = 13.33%

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.