1. A sample of 27 account balances of a credit company showed a mean customer balance of $4,150, but the marketing manager claimed that the mean balance for the population was $4,325. The marketing manager did NOT have the population standard deviation, but the sample standard deviation was found to be $400. Use the p-value approach to conduct a full hypothesis test (all steps) that can be used to determine whether the mean of all account balances is significantly different from $4,325. Let a=.05