The Fred and Barney Cookie Co. has decided to implement statistical quality control to its chocolate chip cookie baking line. The company is concerned that it has been providing too many burned cookies. Two times per day over the last 5 days, the company has taken samples of 250 cookies and counted the number of burned cookies in each sample. A burned cookie is considered a defective cookie. The results are shown below. The company wants to use a percent defective control chart using 3σ control limits. Assume that the data provided is sufficient for preparing the appropriate control charts.
Sample 1 2 3 4 5 6 7 8 9 10 Number of Burned Cookies 5 5 4 6 2 4 6 5 6 7
a) What are the upper and lower control limits? Calculate your results to 3 decimal places (0.xxx).
b) Plot the control chart including the centerline, the UCL the LCL, and the sample values.
c) What would you conclude about the chocolate chip cooking baking line using the percent defective burned cookies as a measure? Explain your decision.
d) Suppose Fred and Barney subscribes to a cookie industry magazine that states that the standard for burned cookies is 2.0% to 6.5%. Comment on Fred and Barney’s process compared to the industry standards