One of the major US tire makers wishes to review its warranty for their rainmaker tire ...

     One of the   major US tire makers wishes to review its warranty for their rainmaker tire.   The warranty is for 40,000 miles. The tire company believes that the tire   actually lasts more than 40,000 miles. A sample 49 tires revealed that the   mean number of miles is 45,000 miles with a standard deviation of 15,000   miles. Test the hypothesis with a 0.05 significance level.