A set of final examination grades in a calculus course was found to be normally distributed with a mean of 69 and a standard deviation of 9. What percentage of students scored between 65 and 89?
A).6568
B)1.000
C).9868
D).3300

Question

Quizplus · Accepted Answer

The z-score for a grade of 65 is (65 - 69) / 9 = -0.44. The z-score for a grade of 89 is (89 - 69) / 9 = 2.22. The area under the normal curve between these two z-scores is 0.6568, which is the percentage of students who scored between 65 and 89.

A Set of Final Examination Grades in a Calculus Course