Question: 9. A discount store issues its own credit card. The credit manager believes that the mean monthly unpaid balance is $400 or less. The level of significance is set at .05. A random check of 172 unpaid balances revealed the sample mean is $407.00 and the standard deviation is $38.00. The manager wants to test if the mean is greater than $400.00. Show the 5 step hypothesis test the manager should use to make her decision.