A researcher determines that students study an average of 80 ± 20 (M ± SD)min/week.Assuming these data are normally distributed,what is the z score for students studying 60 min/week?
A) 1.0
B) -1.0
C) .3413
D) .1587

Question

Quizplus · Accepted Answer

To calculate the z score, we need to first standardize the value using the formula:

z = (x - M) / SD

where x is the value we want to convert to a z score (in this case, x = 60), M is the mean (M = 80), and SD is the standard deviation (SD = 20). Plugging in the values, we get:

z = (60 - 80) / 20 = -1.0

Therefore, the z score for students studying 60 min/week is -1.0, which corresponds to choice B.

A Researcher Determines That Students Study an Average of 80