A phone manufacturer wants to compete in the touch screen phone market. He understands that the lead product has a battery life of just 5 hours. The manufacturer claims that while the new touch phone is more expensive, its battery life is more than twice as long as that of the leading product. In order to test the claim, a researcher samples 45 units of the new phone and finds that the sample battery life averages 10.5 hours with a sample standard deviation of 1.8 hours.

a. Set up the relevant null and the alternative hypotheses.

b. Compute the value of the test statistic.

c. Use the critical value approach to test the phone manufacturer’s claim at α = 0.05.

d. Repeat the analysis with the p-value approach.