A cell phone manufacturer has hired you to estimate the population mean of the battery lifetimes for all phones of their latest model. You decide to measure battery lifetime by recording the time it takes for the battery charge to run out while a tester is streaming videos on the phones continuously. Then you select a random sample of 45 cell phones of the manufacturer's latest model and record their battery lifetimes. Assume that the population standard deviation of the battery lifetimes for that cell phone model (using your method of measurement) is 2.42 hours Based on your sample, follow the steps below to construct a 99%% confidence interval for the population mean of the battery lifetimes for all phones of the manufacturer's latest model. (If necessary, consult a list of formulas.) (a) Click on "Take Sample" to see the results from your random sample of 45 phones of the manufacturer's latest model. Number of phones Sample mean Sample standard Population deviation standard deviation Take Sample 45 1.84 2.42 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 99% 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: nfidance Critical level value Critical value: 99% confidence interval: 0.005 2.576 70.025 1-960 Compute F0.050 1-645 (b) Based on your sample, enter the lower and upper limits to graph the 99% confidence interval for the population mean of the battery lifetimes for all phones of the manufacturer's latest model. 99 % confidence interval 0.on