Scores on standardized intelligence tests are normally distributed with a mean of 100 and a standard deviation of 15.This means that
A) 50% of the population scores between 70 and 100 on standardized intelligence tests.
B) only 5% of the population scores higher than 130 or lower than 70 on standardized intelligence tests.
C) only 5% of the population scores higher than 115 or lower than 85 on standardized intelligence tests.
D) 95% of the population scores between 100 and 130 on standardized intelligence tests.

Question

Quizplus · Accepted Answer

The empirical rule states that for a normal distribution, approximately 95% of the data falls within two standard deviations of the mean. In this case, the mean is 100 and the standard deviation is 15, so 95% of the data falls between 70 and 130. Therefore, only 5% of the population scores higher than 130 or lower than 70.

Scores on Standardized Intelligence Tests Are Normally Distributed with a Mean