Question

The grades on the last art exam had a mean of 75%. Assume the population of grades on art exams is known to be distributed normally, with a standard deviation of 7%. Using the empirical rule, approximately what percent of students earn a score between 75% and 82%? 68% 16% 32% 34%

Answer 1

34%

Explanation:

Well 75+7=82 and one hop on the graph is 34%.

Answer 2

Find the z-score for both 75% and 82% then subtract them.

Z-score for 75%:

75 -75 /7 = 0-7 = 0

Using empirical rule, This translates to a percentile if 50%

Z-score for 82%

82-75 /7 = 7/7 = 1

Using empirical rule, this translates to 84.13%

Answer = 84.13-50 = 34.13% round to 34%