Question: Consider the hypothesis test:

H0 :????800

Ha :????800.

You took a sample of 40 subjects and found that the sample mean was 785, with a sample standard deviation of 95. You are testing at the significance level ????0.05. (10 pts each)

a. Find the border value between the rejection region and the non-rejection region.

b. Using this border value, what does your sample mean tell you? Is the null hypothesis rejected or not?

c. Find the value of ??when the true mean is 780 instead of 800. What is the power of the test in this circumstance?

d. Find the value of ??when the true mean is 750 instead of 800. What is the power of the test in this circumstance?