A standardized test of intelligence is scaled so that the mean IQ is 100, and the standard deviation is
15. On a standardized IQ test, what is the Z score for a person with an IQ of 145?
A)-3
B)2
C)3

Question

A standardized test of intelligence is scaled so that the mean IQ is 100, and the standard deviation is
15. On a standardized IQ test, what is the Z score for a person with an IQ of 145? 
A)-3 
B)2 
C)3

Quizplus · Accepted Answer

To find the Z score, we use the formula Z = (X - µ) / σ, where X is the IQ score, µ is the mean IQ, and σ is the standard deviation. Plugging in the given values, we get Z = (145 - 100) / 15 = 3. Therefore, the Z score for a person with an IQ of 145 is 3. Choice C is the only option that matches this result. The formula for calculating Z score is (X - μ) / σ, where X is the individual's score, μ is the mean, and σ is the standard deviation. Plugging in the values given in the question, we get (145 - 100) / 15 = 3. Therefore, the Z score for a person with an IQ of 145 is 3.

A Standardized Test of Intelligence Is Scaled So That the Mean