If a car traveled 200 miles at an average rate of speed of r miles per hour, the time it took for the trip could be written as: (A) 200/r
(B) r/200
(C) 200r
(D) r200
(E) 200-4

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%