Ewma
Properties
| Center | Gets the center line (target/grand mean). |
| Lambda | Gets the EWMA smoothing constant λ in (0, 1]. |
| Sigma | Gets the sigma estimate used for computing control limits. |
| Target | Gets the target (reference) value used as the starting point of the EWMA recursion. |
| Width | Gets the control-limit width multiplier (typically 3.0). |