Mrs. Jones's Algebra 2 class scored very well on yesterday’s quiz. With one exception, everyone received an A. Within how many standard deviations of the mean do all the quiz grades fall?

Question

91, 92, 94, 88, 96, 99, 91, 93, 94, 97, 95, 97
(1 point)
Responses

2
2

1
1

3
3

4

Answer 1

The mean of the quiz grades is (91+92+94+88+96+99+91+93+94+97+95+97)/12 = 93.25

The standard deviation can be calculated using a calculator or spreadsheet.

After calculating the standard deviation, we can determine that all the quiz grades fall within 2 standard deviations of the mean. Therefore, the answer is 2.