ection 8: 1 Population Mean Section 8.1: Sampling Distribution of Sample Means Remember: When asked to describe any sampling distribution, you are expected to state the center (mean), spread (standard deviation), and shape, as well as justify these by showing work or explaining your reasoning. Exercises A simple random sample of size n = 40 is to be selected from a population with u = 55 and 6 = 12. a) What is the mean and standard deviation of the sample mean, x? Show work. ly normal? Justify your