Atlas Copco ACTA 3000

Printouts from ACTA ACTA 4000 User Guide
120 (136) 2008-12 9836 4171 01
9.2.2 X-bar and Range coefficients table
Table 3 shows coefficients for control charts, used in Control charts equations.
Group size
n
Coefficient
A2
Coefficient
D3
Coefficient
D4
2 1.880 0 3.267
3 1.023 0 2.574
4 0.729 0 2.282
5 0.577 0 2.114
6 0.483 0 2.004
7 0.419 0.076 1.924
8 0.373 0.136 1.864
9 0.337 0.184 1.816
10 0.308 0.223 1.777
11 0.285 0.256 1.744
12 0.266 0.283 1.717
13 0.249 0.307 1.693
14 0.235 0.328 1.672
15 0.223 0.347 1.653
16 0.212 0.363 1.637
17 0.203 0.378 1.622
18 0.194 0.391 1.608
19 0.187 0.403 1.597
20 0.180 0.415 1.585
21 0.173 0.425 1.575
22 0.167 0.434 1.566
23 0.162 0.443 1.557
24 0.157 0.451 1.548
25 0.153 0.459 1.541
Table 3 Coefficients table