Question

Inches:

54, 55.5, 56, 56, 56.5, 57, 58, 58, 58, 58.5,
58.5, 59, 59, 59.5, 60, 60, 60.5, 61, 63, 72


Mrs. Blackwell's class is getting a new student next week. The current students want to predict the height of the new student. They record the height of everyone in the class. Which measure of center should they use to make the prediction and what should be their prediction?
Responses

A the mean and they should predict 59 inchesthe mean and they should predict 59 inches

B the mean and they should predict 58.5 inchesthe mean and they should predict 58.5 inches

C the median and they should predict 59 inchesthe median and they should predict 59 inches

D the median and they should predict 58.5 inchesthe

Answer 1

D — the median, 58.5 inches.

Reason: the 72-inch value is an outlier that would skew the mean, so the median (middle value) is a better predictor. For these 20 heights the median is the average of the 10th and 11th values: (58.5 + 58.5)/2 = 58.5.