Managing for Quality and Performance Excellence 9th Edition by James Evans,William Lindsay

Exercise 39

Widetred, Inc. makes automobile tires that have a mean life of 60,000 miles with a standard deviation of 2,000 miles. Using Excel functions (see Chapter 6), determine the following:
a. What fraction of tires is expected to survive beyond 63,250 miles?
b. What fraction will survive fewer than 56,600 miles?
c. Draw a chart of the reliability function using Excel.
d. What length of warranty is needed so that no more than 5 percent of the tires will be expected to fail during the warranty period?