Table of Constants for Xbar and S Charts
| Sample Size (ni) |
A3 |
B3 |
B4 |
| 2 |
2.659 |
0 |
3.267 |
| 3 |
1.954 |
0 |
2.568 |
| 4 |
1.628 |
0 |
2.266 |
| 5 |
1.427 |
0 |
2.089 |
| 6 |
1.287 |
0.030 |
1.970 |
| 7 |
1.182 |
0.118 |
1.882 |
| 8 |
1.099 |
0.185 |
1.815 |
| 9 |
1.032 |
0.239 |
1.761 |
| 10 |
0.975 |
0.284 |
1.716 |
| 11 |
0.927 |
0.321 |
1.679 |
| 12 |
0.886 |
0.354 |
1.646 |
| 13 |
0.850 |
0.382 |
1.618 |
| 14 |
0.817 |
0.406 |
1.594 |
| 15 |
0.789 |
0.428 |
1.572 |
| 16 |
0.763 |
0.448 |
1.552 |
| 17 |
0.739 |
0.466 |
1.534 |
| 18 |
0.718 |
0.482 |
1.518 |
| 19 |
0.698 |
0.497 |
1.503 |
| 20 |
0.680 |
0.510 |
1.490 |
| 21 |
0.663 |
0.523 |
1.477 |
| 22 |
0.647 |
0.534 |
1.466 |
| 23 |
0.633 |
0.545 |
1.455 |
| 24 |
0.619 |
0.555 |
1.455 |
| 25 |
0.606 |
0.565 |
1.435 |