The standard error of the mean for a sample of 100 is 30.In order to cut the standard error of the mean to 15,we would
A)increase the sample size to 200.
B)increase the sample size to 400.
C)decrease the sample size to 50.
D)decrease the sample size to 25.

Question

Quizplus · Accepted Answer

The standard error of the mean is inversely proportional to the square root of the sample size. Therefore, to cut the standard error of the mean from 30 to 15, we would need to increase the sample size by a factor of 4, which means we need a sample size of 400.

The Standard Error of the Mean for a Sample of 100