Broadtred, Inc. makes automobile tires that have a mean life of 50,000 miles with a standard deviation of 2,500 miles. Using Excel functions (see Chapter 6), determine the following:
a. What fraction of tires is expected to survive beyond 54,000 miles?
b. What fraction will survive fewer than 56,000 miles?
c. What length of warranty is needed so that no more than 2 percent of the tires will be expected to fail during the warranty period?