Jenny has collected the following data on the amount of time (in minutes) taken by a tax preparation service to complete client interviews.

client	time ( minutes)
1	8
2	12
3	26
4	10
5	23
6	21
7	16
8	22
9	18
10	17
11	36
12	9

Compute the sample mean and the sample standard deviation of this sample.

Construct a 98% confidence interval for the population mean interview time. Approximately how large a sample size is required to obtain a 96% confidence interval whole accuracy is +/- 2.0 minutes?