Assignment:
QUESTION
(a) 15 samples of size n = 8 have been taken from a cleaning operation. The average sample range for the 20 samples was 0.016 minute, and the average mean was 3 minutes. Determine the three-sigma control limits for this process.
(b) 15 samples of size n = 10 observations have been taken from a milling process. The average sample range is 0.01 centimetres. Determine upper and lower control limits for sample ranges.
(c) Determine which of these three processes are capable:
|
Process
|
Mean
|
Standard Deviation
|
Lower Specification
|
Upper Specification
|
|
1
|
6.0
|
0.14
|
5.5
|
6.7
|
|
2
|
7.5
|
0.10
|
7.0
|
8.0
|
|
3
|
4.6
|
0.12
|
4.3
|
4.9
|