Esp You work for a chain of hamburger restaurants and want to estimate the population mean of the wait times in the drive-thru for all customers. To do so, you select a random sample of 40 of the chain's drive-thru customers and record the wait time in the drive-thru for each. Assume it is known that the population standard deviation of the wait times in the drive-thru for the hamburger chain's restaurants is 2.91 minutes. Based on your sample, follow the steps below to construct a 90%% confidence interval for the population mean of the wait times in the drive-thru for all customers. (If necessary, consult a list of formulas.) (a) Click on "Take Sample" to see the results from your random sample of 40 customers. Number of Sample mean Sample standard Population customers deviation standard deviation Take Sample 40 5.38 2.79 2.91 Enter the values of the sample size, the point estimate for the population mean, the population standard deviation, and the critical value you need for your 90% confidence interval. (Choose the correct critical value from the table of critical values provided.) When you are done, select "Compute". Sample size: Standard error: Point estimate: Population standard deviation: Margin of error: nfidence Critical level value Critical value: 0.005 2.576 90% confidence interval: 0.025 1.960 Compute 90% -0.050 1-645 (b) Based on your sample, enter the lower and upper limits to graph the 90% confidence interval for the population mean of the wait times in the drive-thru for all customers. 90% confidence interval: 0.00 10.04 10 00