In a normal distribution of IQ scores, where the mean is 100 and the standard deviation is 10, what percent of the cases have IQ scores from 90 to 110?

Question

Quizplus · Accepted Answer

In a normal distribution, 68% of the cases fall within one standard deviation (SD) of the mean. Since the mean is 100 and the standard deviation is 10, one SD on either side of the mean covers the range from 90 to 110. Therefore, 68% of the cases have IQ scores from 90 to 110. Therefore, the correct answer is D.

In a Normal Distribution of IQ Scores, Where the Mean