Managing for Quality and Performance Excellence 10th Edition by James Evans ,William Lindsay

Exercise 9

Note: Data sets for several problems are available in the Excel workbook C07Data in the Student Companion Site for this chapter. Click on the appropriate worksheet tab as noted in the problem (e.g., Prob. 7-5, etc.) to access the data.
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. Draw a chart of the reliability function using Excel.
d. 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?