Assignment:
Q: Auto pistons at Wemming Chung'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 and 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 |
5.0 |
| 5 |
156.6 |
4.5 |
a) What are the UCL x and LCL x (line on top of x) , using 3s? Plot the data.
b) What are the UCL R and LCL R , using 3s? Plot the data.
c) Is the Process in Control?