5) If an IQ test has a mean of 100 and a standard deviation of 15, use z tables to find what percentage of people would score between the mean and 120:
A) 27.34%
B) 40%
C) 40.82%
D) 41%

Question

Quizplus · Accepted Answer

Using a z-score formula: 
z = (score - mean) / standard deviation
z = (120 - 100) / 15
z = 1.33
Looking at a z-table, we see that the percentage of people scoring between the mean and 120 is 40.82%, which corresponds to answer choice C.

5) If an IQ Test Has a Mean of 100