Question: Sales personnel for Skillings Distributors submit weekly reports listing the customer contacts made during the week. A sample of 65 weekly reports showed a sample mean of 19.5 customer contacts per week. The sample standard deviation was 5.2.

(a) Provide 90% confidence intervals for the population mean number of weekly customer contacts for the sales personnel.

(b) Provide 95% confidence intervals for the population mean number of weekly customer contacts for the sales personnel.