A population of scores is normally distributed with a mean of 100 and a standard deviation of 20. Approximately percent of the scores fall in the interval between 100 and 120.
A)14
B)34
C)68
D)84

Question

Quizplus · Accepted Answer

In a normal distribution, approximately 34% of the scores fall between the mean and one standard deviation above the mean. Since the interval from 100 to 120 is exactly that (with 100 being the mean and 120 being one standard deviation above the mean, given the standard deviation is 20), about 34% of the scores fall within this range.

A Population of Scores Is Normally Distributed with a Mean