A manufacturer produces bolts for commercial use, and tests the quality of production by choosing a sample of 5 bolts every 2 hours from production. Because of variation, not all bolts have the same length. Shown below are 8 samples. Use the information below to construct an x bar chart, and R chart, and determine if the process is capable and in control.
Sample 1: 8.01, 7.99, 7.99. 8.00, 7.98
Sample 2: 8.03, 7.96, 8.01, 8.02, 7.97
Sample 3: 7.96, 7.97, 7.96, 7.99, 8.01
Sample 4: 8.00, 8.01, 7.97, 8.01, 7.99
Sample 5: 8.02, 8.03, 7.99, 8.01, 8.02
Sample 6: 8.02, 8.01, 7.97, 8.00, 8.01
Sample 7: 8.03, 8.04, 8.03, 8.00, 7.99
Sample 8: 7.96, 7.99, 8.02, 8.01, 7.98
Prepare your charts using any tool you wish, i.e., PowerPoint, MS Word, Excel, or free tools such as Apache OpenOffice and portable and installable versions of LibreOffice. Save your document as a pdf file for uploading to your discussion area. Answer the following questions:
Is the process capable and in control?
Why do we need both an x bar and R chart?
When a process is in control, is it producing acceptable levels of quality?
