The Control Panel contains the current values for the chart parameters. The current values are in boxes that enable you to update the parameter values.
The following options appear in the Control Panel:
Target
The known value of the mean. This is the value of the center line in the chart. By default, this parameter is set to the Target value in the Spec Limits column property for the Y column. If the Y column does not have a Target value in the Spec Limits column property, this parameter is set to the overall average of the Y column.
The Target value cannot be edited in these situations:
– If you specified the Center Data option in the launch window.
– If the Y variable has a Spec Limits column property that contains a value for Target. However, you can select the Use Overall Mean for Target option in the red triangle menu to switch between the Target value in the Spec Limits column property and the overall mean of the Y variable.
Sigma
The known value of the standard deviation. By default, this parameter is set to the average moving range of the Y column. If there is a Subgroup variable, the Sigma parameter is set to the average of the moving ranges of the subgroup means.
Note: The default Sigma value calculation does not include excluded rows.
Lambda
The value of the smoothing constant for weighting prior samples. By default, this parameter is set to 0.2.
*Using Centered Data
The presence of this text indicates that the Centered Data option was selected in the launch window and that the values in the EWMA chart and X chart are centered around the Target value.