Constants for Xbar and R Charts
| Sample Size (ni) |
A2 |
D3 |
D4 |
| 2 |
1.880 |
0 |
3.267 |
| 3 |
1.023 |
0 |
2.575 |
| 4 |
0.729 |
0 |
2.282 |
| 5 |
0.577 |
0 |
2.115 |
| 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 |
0.284 |
1.716 |
| 13 |
0.249 |
0.308 |
1.692 |
| 14 |
0.235 |
0.329 |
1.671 |
| 15 |
0.223 |
0.348 |
1.652 |
| 16 |
0.212 |
0.364 |
1.636 |
| 17 |
0.203 |
0.379 |
1.621 |
| 18 |
0.194 |
0.392 |
1.608 |
| 19 |
0.187 |
0.404 |
1.596 |
| 20 |
0.180 |
0.414 |
1.586 |
| 21 |
0.173 |
0.425 |
1.575 |
| 22 |
0.167 |
0.434 |
1.566 |
| 23 |
0.162 |
0.443 |
1.557 |
| 24 |
0.157 |
0.452 |
1.548 |
| 25 |
0.153 |
0.459 |
1.541 |