In a set of survey results, the mean is 15 and the standard deviation is 3. With these numbers we know that 99% of the scores are between ________.
A) 6 and 24
B) 12 and 18
C) 0 and 30
D) 9 and 21

Question

Quizplus · Accepted Answer

The mean is 15 and the standard deviation is 3. 99% of the scores are within 2.58 standard deviations of the mean. So, 99% of the scores are between 15 - 2.58 * 3 = 6 and 15 + 2.58 * 3 = 24.

In a Set of Survey Results, the Mean Is 15