Originally Posted by

**JohnM**
CORRECTIONS BELOW IN RED - sorry!

Michelle,

Welcome to the forum.

You don't need to find the mean in this problem, since you are asked to find the number of __standard errors away from the mean__ that correspond to probability levels .05 and .15.

Using the standard normal distribution, find the z-score that corresponds to the upper-tail probability of .05, and then multiply that z-score by the standard error of the mean (1.5 / sqrt(64)). That will tell you how far away from the mean it is.

Follow the same logic for a probability of .15.

JohnM