On a T score distribution, 68% of the cases must fall between T scores of
A) 50 and 60
B) 0 and 10
C) 40 and 50
D) 40 and 60

Question

Quizplus · Accepted Answer

On a T score distribution, 68% of the cases fall within one standard deviation of the mean. The mean of a T score distribution is 50, and one standard deviation is 10 (because the standard deviation of a T score distribution is always 10). Therefore, 68% of cases fall within 10 points above or below the mean of 50, which corresponds to a range of T scores from 40 to 60. Therefore, choice D is the best answer.

On a T Score Distribution, 68% of the Cases Must