Chapter 5 - Normal Probability Distributions - Section 5.1 Introduction to Normal Distributions and the Standard Normal Distribution - Exercises - Page 242: 9

It is correct because the mean of a standard distribution is one. It's standard deviation is also one. If we call the standard normal variable "z" and do the mean divided by the standard deviation. We get the answer to say z=0. Therefore the statements in the problem statement are correct.

1) set a standard normal variable 2) plug in values for the standard normal curve for the mean and the standard deviation 3) divide the mean by the standard deviation 4) the value determines whether the problem statements are correct