After writing his Biology exam, Sam's professor announces that the grades from the exam were normally distributed with a mean of 60 and a standard deviation of 10. Sam's grade on the exam was 70. Approximately what percentage of the class had a grade on the exam that was higher than Sam's?

Question

Quizplus · Accepted Answer

Sam's grade of 70 is one standard deviation above the mean (60 + 10). In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, so 34% is above the mean. Therefore, 50% - 34% = 16% of the class scored higher than Sam.

After Writing His Biology Exam, Sam's Professor Announces That the Grades