Help me I need help pleas

If you are just building your payment history, how many points from a perfect score will you possibly miss?

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? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much