Problem
Six samples of n=10 observations have been obtained and the sample means and ranges were computed in minutes:
• Determine the upper and lower limits for sample mean and range control charts.
• Is the process in control?
|
Sample
|
Mean
|
Range
|
|
1
|
2.83
|
0.32
|
|
2
|
3.10
|
0.4
|
|
3
|
3.08
|
0.12
|
|
4
|
1.98
|
0.36
|
|
5
|
3.03
|
0.46
|
|
6
|
2.07
|
0.45
|