1) 2a × 2a 2) 3a × 4a
3) 2b × 6b
4) 5 × 2a × a
5) 3a × 4a × 2a
6) 5a × 3a × a × a
7) 2a × 2 × 2a
8) 3a × 3a × 3a

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%