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

Exercise 43

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.
Sparkly Cleaning Co. has found that standard size offices have a standard deviation of 5 minutes for their cleaning time. The operations manager knows that 95 percent of the offices require more than 120 person-minutes to clean. However, she wishes to find out the average cleaning time for the offices. Can you calculate that for her?