Question

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. If a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. What is the margin of error of the sample mean?

Answer 1

the margin of error tends to be related to a confidence interval. otherwise it reads to me like you want to determine the standard error instead