Formulas and Tables
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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
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Tabular values for X and range charts
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Subgroup
Size |
E2
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D4
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1
|
2.660
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3.268
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2
|
2.660
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3.268
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3
|
1.772
|
2.574
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4
|
1.457
|
2.282
|
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5
|
1.290
|
2.114
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6
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1.184
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2.004
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7
|
1.109
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1.924
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8
|
1.054
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1.864
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9
|
1.010
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1.816
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10
|
0.975
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1.777
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