The scores on the Wechsler Adult Intelligence Scale are approximately Normal, with $\mu$ = 100 and $\sigma$ = 15. The proportion of adults with scores between 80 and 120 is closest to:
A)0.50.
B)0.66.
C)0.82.
D)0.99.

Question

Quizplus · Accepted Answer

Scores between 80 and 120 on the Wechsler Adult Intelligence Scale represent scores within one standard deviation (15 points) of the mean (100). In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean. However, the question asks for the proportion between 80 and 120, which is within ±1.33 standard deviations of the mean. This range actually encompasses closer to 82% of the population, making option C the closest answer.

The Scores on the Wechsler Adult Intelligence Scale Are Approximately μ\muμ

The Scores on the Wechsler Adult Intelligence Scale Are Approximately $\mu$