Precision Manufacturing has a government contract to produce stainless steel rods for use in militar
Question: Precision Manufacturing has a government contract to produce stainless steel rods for use in military aircraft. Each rod is required to be 20 millimeters in diameter. Each hour, random samples of size n = 4 rods are measured to check process control. Five hours of observations yielded the following:
Diameter | ||||
Time | Rod 1 | Rod 2 | Rod 3 | Rod 4 |
9 A.M. | 19.8 | 20.4 | 19.9 | 20.3 |
10 A.M. | 20.1 | 20.2 | 19.9 | 19.8 |
11 A.M. | 19.9 | 20.5 | 20.3 | 20.1 |
Noon | 19.7 | 19.8 | 20.3 | 20.2 |
1 P.M. | 19.7 | 20.1 | 19.9 | 19.9 |
Using these data and the table below, construct limits for xbar- and R-charts. Is the process in control?
Control Chart Limits Factors | |||
Sample Size n | Mean Factor A2 | Upper Range D4 | Lower Range D3 |
2 | 1.880 | 3.628 | 0 |
3 | 1.023 | 2.574 | 0 |
4 | 0.729 | 2.282 | 0 |
5 | 0.577 | 2.114 | 0 |
6 | 0.483 | 2.004 | 0 |
7 | 0.419 | 1.924 | 0.076 |
8 | 0.373 | 1.864 | 0.136 |
9 | 0.337 | 1.816 | 0.184 |
10 | 0.308 | 1.777 | 0.223 |
12 | 0.266 | 1.716 | 0.284 |
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Solution: The solution file consists of 4 pages
Type of Deliverable: Word Document![](/images/msword.png)
Type of Deliverable: Word Document
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