IQ scores based on the Wechsler Adult Intelligence Scale (WAIS) are assumed to be normally distributed with a mean of 100 and a standard deviation of 15. What is the z-score for an IQ of 125?
A) z = -1.25
B) z = 1.25
C) z = 1.67
D) z = 5.05

Question

Quizplus · Accepted Answer

The formula for calculating z-score is (observed value - mean)/standard deviation. Plugging in the values, we get (125-100)/15 = 1.67. Therefore, the z-score for an IQ of 125 is 1.67, which corresponds to answer choice C.

IQ Scores Based on the Wechsler Adult Intelligence Scale (WAIS)