You have changed your return and refund policy to reduce fraudulent returns. You believe that this has reduced the average amount of returns from the previous average of $120 per return. To evaluate this, you get a sample of 81 return records and calculate the sample average which is 117. Suppose that the population standard deviation is 9. Use an alpha of 1% and evaluate this using a hypothesis test.

What is the largest value for x-bar that will allow you to reject Ho?

What is the probability that you will reject Ho if =119?

Fill in the probabilities in the table below. Also indicate alpha, confidence beta and power.

Truth in Population

What test concludes	Ho is true in population	Ho not true in population
Reject Ho
Not reject Ho