If the mean on a test is 90 and the standard deviation is 10,a person with a z-score of -1.0 scored which of the following on the test?
A) 70
B) 80
C) 90
D) 110

Question

Quizplus · Accepted Answer

The formula for calculating a z-score is:

z = (x - μ) / σ

where z is the z-score, x is the raw score, μ is the population mean, and σ is the population standard deviation.

We are given that the population mean is 90 and the population standard deviation is 10. We are also given that the z-score is -1.0.

Substituting in the formula, we get:

-1.0 = (x - 90) / 10

Solving for x, we get:

x = 80

Therefore, the person with a z-score of -1.0 scored an 80 on the test.

If the Mean on a Test Is 90 and the Standard