At the US Open Tennis Championship a Statistician Keeps Track of Every

Multiple Choice

At the U.S. Open Tennis Championship a statistician keeps track of every serve that a player hits during the tournament. The statistician reported that the mean serve speed of a particular player was 100 miles per hour (mph) and the standard deviation of the serve speeds was 15 mph. Using the z-score approach for detecting outliers, which of the following serve speeds would represent outliers in the distribution of the player's serve speeds?

Speeds: 50 mph, 80 mph, and 105 mph

A) 50 is the only outlier.
B) 50, 80, and 105 are all outliers.
C) 50 and 80 are both outliers, 105 is not.
D) None of the three speeds are outliers.