The following data show the values of sample mean (\(\overset{-}{X}\)) and its range (R) for the samples of size five each. Calculate the values for control limits for mean , range chart and determine whether the process is in control.
| Sample number |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
| Mean |
11.2 |
11.8 |
10.8 |
11.6 |
11.0 |
9.6 |
10.4 |
9.6 |
10.6 |
10.0 |
| Range |
7 |
4 |
8 |
5 |
7 |
4 |
8 |
4 |
7 |
9 |
( conversion factors for n=5, A2=0.58, D3=0 and D4=2.115)
