Good evening, I don't know how to work this problem. Can you please assist and show the work sheet, thanks.

MGMT 4630 SPC Assignment #3 Read the scenario below. Then construct and interpret the appropriate control charts. Exercise Objective: Construct and interpret statistical process control charts. Course Learning Objective: Use a variety of current industry quality tools for measuring and monitoring quality The manager of an oil and lube business wanted to monitor its process for its basic oil change service. One of the companys stated goals is to provide the oil change and lube in 15 minutes (or less). He took a sample of 25 randomly selected customers that received this service each day for 20 days. He recorded the number of cars on which the service was completed in 15 minutes or less. 1) Which type of control chart is should be used (np, p, c, or u)? Clearly explain why? 2) Develop the appropriate control chart(s) and examine the oil change process. 3) Does the oil change process appear to be stable during the period of time when the observations were made? Explain why or why not. (Consider the run tests, but you do not have to submit a table of those results.) Special Note: There are two alternative ways to evaluate the process. You can monitor the number of cars completed on time OR the number of car not completed on time. Either way is equivalent and acceptable. Regardless of which option you chose, you will not have one control limit. Remember, than you cannot count more than the number of cars that were included in the sample AND you cannot have less than 0. Therefore, in one instance, you will not have an UCL and in the other, you will not have an LCL. Make sure that you reflect this in your chart. Instructions You may NOT use Excel for performing calculations. Submit your calculations (neat and organized) Submit a very neatly prepared page of handwritten calculations. Round all calculations to two (2) decimal places except for and (if used). Round and to three (3) decimal places. Plot the control chart using pencil and pen and a straight edge. Make it to scale and neat. The charts must clearly show and label the control limits, the ABC zones and the centerline. The y-axis must be clearly labeled with these components, i.e. show the numeric values. Neatness counts. Data Day

Cars completed on Time 1 21 2 22 3 20 4 19 5 19 6 17 7 23 8 21 9 17 10 21 11 20 12 19 13 16 14 17 15 17 16 16 17 24 18 16 19 17 20 22