testers are streaming videos on the phones continuously The manufacturer claims that the population mean of the battery lifetimes of all phones of their latest model is 5 13 hours As a researcher for a consumer information service you want to test that claim To do so you select a random sample of 45 cell phones of the manufacturer s latest model and record their battery lifetimes Assume it is known that the population standard deviation of the battery lifetimes for that cell phone model is 2 42 hours Based on your sample follow the steps below to construct a 90 confidence interval for the population mean of the battery lifetimes for all phones of the manufacturer s latest model Then state whether the confidence interval you construct contradicts the manufacturer s claim 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 Take Sample Sample size 0 Point estimate 0 Population standard deviation 1 Critical value 0 Compute 0 00 Number of phones 45 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 H 0 00 Sample mean 2 00 5 36 4 00 Sample standard Standard error Margin of error 90 confidence interval deviation 90 confidence interval b Based on your sample graph the 90 confidence interval for the population mean of the battery lifetimes for all phones of the manufacturer s latest model 5 00 2 02 Enter the lower and upper limits on the graph to show your confidence interval For the point enter the manufacturer s claim of 5 13 hours 6 00 Population standard deviation 2 42 8 00 X Critical values 0 005 2 576 0 010 2 326 20 025 1 960 0 050 1 645 20 100 1 282 10 00 10 00 a BIRO M