Jim Is a Quality Control Manager at a Clothing Manufacturing

Essay

Jim is a quality control manager at a clothing manufacturing company. He studies a quality problem where zippers are purchased from an outside supplier. He discovers that they are poorly constructed. When the zipper is manufactured correctly, it should have a mean length of 15 inches and a range of 0.5 inches. Jamie proposes that 25 samples of five observations each should be collected on a daily basis. He plans to prepare control charts to monitor the progress of the supplier's quality performance on the zippers.
a.What are the upper and lower control limits and center line for an R-chart?
b.What are the upper and lower control limits and center line for an x-bar chart?