Question: A random sample of 15 health maintenance organizations (HMOs) was selected. For each HMO, the co-payment (in dollars) for a doctor's office visit was recorded. The results are as follows: 12,12,8,9,9,10,7,9,6,7,10,5,7,10,6

Under the assumption that co-payment amounts are normally distributed, find a 90%confidence interval for the mean co-payment amount in dollars. Then complete the table below.