Zack had a score of 90 in a class with a mean of 80 and a standard deviation of 10.His z-score is
A) +2.0.
B) +1.0.
C) -1.0.
D) -2.0.

Question

Quizplus · Accepted Answer

The formula for calculating the z-score is:

z = (x - μ) / σ

where x is the individual score, μ is the population mean, and σ is the population standard deviation.

In this case, Zack's score is 90, the population mean is 80, and the population standard deviation is 10. Plugging these values into the formula, we get:

z = (90 - 80) / 10

z = 1.0

Therefore, Zack's z-score is +1.0.

Zack Had a Score of 90 in a Class with a Mean