Suppose that we wish to test H0 : m 20 versus Ha : m 20, where the population standard devia- tion is known to equal 7. Also, suppose that a sample of 49 measurements randomly selected from the population has a mean equal to 18.

a Calculate the value of the test statistic z.

b By comparing z with a critical value, test H0 versus Ha at a .01.

c Calculate the p-value for testing H0 versus Ha .

d Use the p-value to test H0 versus Ha at each of a .10, .05, .01, and .001.

e How much evidence is there that H0 : m 20 is false and Ha : m 20 is true?