Question

While reviewing the sample of audit​ fees, a senior accountant for the firm notes that the fee charged by the​ firm's accountants depends on the complexity of the return. A comparison of actual charges therefore might not provide the information needed to set next​ year's fees. To better understand the fee​ structure, the senior accountant requests a new sample that measures the time the accountants spent on the audit. Last​ year, the average hours charged per client audit was 3.01 hours. A new sample of 15 audit times shows the following times in hours. Complete parts a and b below.

3.2        4.7        3.7        3.3        3.4

3.7        2.9        3.3        4.6        4.1

3.1        3.5        3.8        2.8        3.8

The 90​% confidence interval to estimate the mean audit time is from __________ to __________

​(Round to two decimal places as​ needed.)

Answer 1