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 $700. To determine if this cost haschanged, the firm randomly samples 34

client audit fees. The sample mean audit cost was $670 with a standard deviation of $65. Complete parts a and b below.

a) Develop a 90% confidence interval estimate for the mean audit cost.

90% confidence interval for the mean audit cost is left parenthesis $ nothing comma $ nothing right parenthesis.

(Round to the nearest dollar asneeded.)

b) Based on your confidenceinterval, what do you think of the claim that the mean cost haschanged?

A.

The interval does not contain

doesnotcontain the historical mean $700

700, which does not support

doesnotsupport the claim that the mean cost has changed.

B.

The interval contains

contains the historical mean $700

700, which supports

supports the claim that the mean cost has changed.

C.

The interval does not contain

doesnotcontain the historical mean $700

700, which supports

supports the claim that the mean cost has changed.

D.

The interval contains

contains the historical mean $700

700, which does not support

doesnotsupport claim that the mean cost has changed.

Click to select your answer(s).