Question

Scores on a University exam are normally distributed with a mean of 68 and a standard deviation of 9. Using the 68-95-99.7 rule, what percentage of students score above 77?

Answer 1

0.1585, or 15.85%

Explanation:

On a standard bell curve, the area from 77 to 100 falls within the 95.45 to 99.73 range.

99.73 - 68.27 = 31.46

31.46 / 2 =15.73

99.7 - 68 = 31.7

31.7 / 2 = 15.85