1. What assumptions must be met in order to carry out a t test about a population mean?
2. How do we decide whether to use a z test or a t test when testing a hypothesis about a population mean?
3. Suppose that a random sample of nine measurements from a normally distributed population gives a sample mean of x = 2.57 and a sample standard deviation of s = .3. Use critical values to test H0: m = 3 versus Ha: m* 3 using levels of significance a = .10, a = .05, a = .01, and a = .001.
4. Consider the e-billing case. The mean and the standard deviation of the sample of n = 65 payment times are x = 18.1077 and s = 3.9612. (1) Test H0: m = 19.5 versus Ha: m 19.5 by setting a equal to .01 and using a critical value rule. (2) Interpret the (computer calculated) p-value of .0031 for the test. That is, explain how much evidence there is that H0 is false.