If your sample mean is 100, your population average is 90, and your standard error of the mean is 10, what is your observed z value?
A)0
B)−.1
C)1
D)−1

Question

Quizplus · Accepted Answer

The formula for z-value is: 
z = (sample mean - population mean) / standard error of the mean

Thus, 
z = (100 - 90) / 10 
z = 1

Therefore, the observed z-value is 1, which corresponds to choice C.

If Your Sample Mean Is 100, Your Population Average Is