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

Exercise 41

Note: Data sets for many problems in this chapter are available in the Excel workbook C06Data.xlsx on the Student Companion Site. Click on the appropriate worksheet tab as noted in the problem (e.g., Prob. 6-1) to access the data. In addition, the spreadsheet templates illustrated in the chapter are also available to aid in solving many of these problems.
A new product is being tested by Zed Electronics to determine if it will continue to operate in a stable fashion under a variety of conditions. A sample of 400 items were tested, and 60 failed the test. Determine a 90 percent confidence interval for the population proportion.