Problem:
On a certain math exam, of the students got 70 points, got 80 points, got 85 points, got 90 points, and the rest got 95 points. What is the difference between the mean and the median score on this exam?
Answer Choices:
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Solution:
The percentage of students getting 95 points is
so the mean score on the exam is
Since fewer than half of the scores were less than 85 , and fewer than half of the scores were greater than 85 , the median score is 85 . The difference between the mean and the median score on this exam is .
The problems on this page are the property of the MAA's American Mathematics Competitions