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Auto pistons at yongpin zhou’s plant in shanghai are produced in a
S6.7: Auto pistons at Yongpin Zhou’s plant in Shanghai are produced in a forging process, and the diameter is a critical factor that must be controlled. From sample sizes of 10 pistons produced each day, the mean the range of this diameter have been as follows:
|
Day |
Mean (mm) |
Range(mm) |
|
1 |
156.9 |
4.2 |
|
2 |
153.2 |
4.6 |
|
3 |
153.6 |
4.1 |
|
4 |
155.5 |
5 |
|
5 |
156.6 |
4.5 |
a.What is the value x bar?
b. What is the value of R bar?
c. What are the UCL_x bar and LCL_x bar using 3 sigma?
S.6.15: The results of inspection of DNA samples taken over the past 10 days are given below. Sample size is 100.
|
Day |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
|
Defectives |
7 |
6 |
6 |
9 |
5 |
6 |
0 |
8 |
9 |
1 |
a) Construct a 3-sigma p-chart using this information.
b) If the number of defectives on the next three days are 12, 5 and 13, is the process in control?