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

Exercise 14

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.
J. McWilliams Swim Club is trying to calibrate their chlorine pump to ensure that the right amount of chlorine (1.0-1.5 ppm of free chlorine) is mixed into the water. Thirty samples of 4 readings at random times during the week were taken. These data can be found in the worksheet Prob. 826 in the C08Data.xlsx file.
a. Compute the mean and range of each sample, calculate control limits, and plot them on
and R control charts.
b. Does the process appear to be in statistical control? Calculate descriptive statistics that may help you to determine the answer to this question. What evidence is there for your conclusion?