A triangle with base = 10 in. and height = 3 in. a right triangle with base = 9 in. and height = 4 in.
a rectangle with base = 12 in. and height = 3 in.
a square with base = 6 in.

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%