About 95 percent of scores fall between ________ standard deviation(s) above and below the mean in a normal distribution.
A) four
B) one
C) three
D) two

Question

Quizplus · Accepted Answer

The empirical rule states that approximately 68% of scores fall within one standard deviation of the mean, about 95% of scores fall within two standard deviations of the mean, and almost all (99.7%) scores fall within three standard deviations of the mean in a normal distribution. Therefore, the correct answer is D, which refers to two standard deviations above and below the mean.

About 95 Percent of Scores Fall Between ________ Standard Deviation(s)