Quality Advisor

A free online reference for statistical process control, process capability analysis, measurement systems analysis, and control chart interpretation, and other quality metrics.

Sigma

Sigma of the individuals (actual sigma)

sigma of the individuals formula

Estimated sigma

estimated sigma formulas

Subgroup Size
d2
Subgroup Size
d2
2
1.128
14
3.407
3
1.693
15
3.472
4
2.059
16
3.532
5
2.326
17
3.588
6
2.534
18
3.640
7
2.704
19
3.689
8
2.847
20
3.735
9
2.970
21
3.778
10
3.078
22
3.819
11
3.173
23
3.858
12
3.258
24
3.895
13
3.336
25
3.931