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 400.
B) decrease the sample size to 50.
C) decrease the sample to 25.
D) increase the sample size to 200.

Question

Quizplus · Accepted Answer

The standard error of the mean is inversely proportional to the square root of the sample size. Therefore, if we want to cut the standard error in half, we need to quadruple the sample size. So, increasing the sample size to 400 will result in a standard error of 15.

The Standard Error of the Mean for a Sample of 100