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 8 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: 72 mph, 108 mph, and 116 mph

A) 72, 108, and 116 are all outliers.
B) None of the three speeds is an outlier.
C) 72 is the only outlier.
D) 72 and 108 are both outliers, but 116 is not.

Question

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 8 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: 72 mph, 108 mph, and 116 mph

Speeds: 72 mph, 108 mph, and 116 mph

A) 72, 108, and 116 are all outliers.
B) None of the three speeds is an outlier.
C) 72 is the only outlier.
D) 72 and 108 are both outliers, but 116 is not.

Quizplus · Accepted Answer

A z-score greater than 2 or less than -2 is typically considered an outlier. The z-score for 72 mph is -3.5, making it an outlier. The z-scores for 108 mph and 116 mph are 1 and 2, respectively, which are not considered outliers.

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