Problem 1 The advertised claim for batteries for cell phones is set at 48 operating hours with proper charging procedures. A study of 2000 batteries is carried out and 21 stop operating prior to 48...

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Extracted text: Problem 1 The advertised claim for batteries for cell phones is set at 48 operating hours with proper charging procedures. A study of 2000 batteries is carried out and 21 stop operating prior to 48 hours. The population standard deviation is thought to be 1.75 hours and the sample mean from the 2000 batteries was 50.3 hours. a) Do these experimental results support the claim that less than 1.5% of the company's batteries will fail during the advertised time period, with proper charging procedures? Use a hypothesis- testing procedure with alpha = 0.01 b) Compute a 99% confidence bound to answer question in part a). c) Is there evidence to support the claim that the mean battery life exceeds 48 hours? Use a hypothesis-testing procedure with alpha = 0.01 d) Compute an appropriate confidence bound to answer question in part c). Use alpha = 0.01