Some accounting firms give the client an option to pay a fee when the tax return is completed that guarantees tax advices and support from the accountant if the client were audited. A large accounting firm is trying to determine what fee to charge for nextyear's returns. In previousyears, the actual mean cost to the firm for attending a client audit session was $650. To determine if this cost haschanged, the firm randomly samples 35 client audit fees. The sample mean audit cost was $690 with a standard deviation of $75. Complete parts a and b below.

a) Develop a 95% confidence interval estimate for the mean audit cost.

The 95% confidence interval for the mean audit cost is $

(Round to the nearest dollar asneeded.)