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

Exercise 86

Note: Data for many of the problems in this chapter can be found in the Excel workbook C08Data.xlsx on the Student Companion Site. Click on the appropriate worksheet tab as noted in the problem (e.g., Prob. 8-6, etc.) to access the data.
El Grande Toro Restaurante advertises that customers will have their orders taken within three minutes after being seated. Management wants to monitor average times, as it is such an important guarantee for business. Construct
and s -charts for the data given in the worksheet Prob. 8-35 in the C08Data.xIsx file on the Student Companion Site for this chapter.
a. Compute the sample means and the average standard deviation, calculate the control limits, and plot them on control charts.
b. Does the process appear to be in statistical control? Why or why not?
c. Calculate the process capability statistics, using three minutes as the upper tolerance limit and zero as the lower tolerance limit. What recommendation would you make to management concerning the process, based on these findings?