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Individuals and moving range chart formulas
The most common (and recommended) method of computing control limits for an individuals chart based on 3
standard deviations is:
Individuals (X)
Upper control limit:
|
Lower control limit:
|
Moving Range
Upper control limit:
|
Lower control limit:
|
Subgroup
Size |
E2
|
D4
|
1 |
2.660 |
3.268 |
2 |
2.660 |
3.268 |
3 |
1.772 |
2.574 |
4 |
1.457 |
2.282 |
5 |
1.290 |
2.114 |
6 |
1.184 |
2.004 |
7 |
1.109 |
1.924 |
8 |
1.054 |
1.864 |
9 |
1.010 |
1.816 |
10 |
0.975 |
1.777 |
|
