A major U.S. tire maker wants to review it's warranty for their rainmaker tire. The warranty covers at most 40,000 miles. The tire maker would like to conduct a hypothesis test to determine if it can be concluded that the average number of tire miles is higher than 40,000 miles. A sample of 49 tires revealed that the average number of miles is 45,000 miles. Assume the population standard deviation is 15,000 miles.
A) Develop a null hypothesis and an alternative hypothesis?
B) If conducting this hypothesis testing at the significance level of 0.05, what is the critical value for this testing that you should be using?
C) Calculate the test statistic?
D) Compare the test statistic in part c to the critical value in part b and then reach a statistical conclusion?
E) Translate the statistical conclusion in part d into a business decision?