PCA Results - Quality Tab

Select the Quality tab of the PCA Results dialog box to access options to generate a variety of Shewhart control charts for the original variables and scores particular to a principal component. Shewhart charts are standard graphical tools widely used in statistical quality control. The general approach to quality control charting is straightforward:

Extract samples of a certain size from the ongoing production process. Then produce line charts of the variability in those samples, and consider their closeness to target specifications. If a trend emerges in those lines or if samples fall outside pre-specified limits, the process is declared to be out of control and the operator will take action to find the cause of the problem. See Quality Control Charts for further details.

Element Name	Description
Variable	The following options are displayed in the Variable group box: Use the variable drop-down list to select an analysis variable for which you want to generate a control chart. Control charts can be Shewhart individual, Shewhart mean/range, or Shewhart Mean/std (see Properties below).
Variable control chart	After selecting an analysis variable and a control chart type from the Properties group box, click this button to generate a control chart (see Quality Control Charts for more details). Data cases falling outside the lower or upper bounds of the control limit will be shown in red.
	Click this button to generate a spreadsheet of the original variables, together with the lower and upper bounds for the control and warning limits, as well as data relating to its moving R chart.
Score	The following options are in the Score group box: Use the component drop-down list to select a principal component for which you want to generate a control chart. Control charts can be Shewhart individual, Shewhart mean/range, or Shewhart Mean/std (see Properties below).
Score (t) control chart	After selecting a component and a control chart type in the Properties group box, click this button to generate a control chart (see Quality Control Charts for more detail). Data cases falling outside the lower or upper bounds of the control limit will be shown in red.
	Click this button to generate a spreadsheet of scores for the principal component selected from the Component drop-down list, together with the lower and upper bounds for the control and warning limits, as well as data relating to its moving R chart.
Properties	The following options are displayed in the Properties group box: Select one of the options in the chart type drop-down list to determine the type of the control chart you want to generate. Selections include: Shewhart individual, Shewhart mean/range, and Shewhart Mean/std.
User-defined target	Select this check box and enter the estimated target in the adjacent box.
User-defined sigma	Select this check box and enter in the adjacent box the value of the estimates sigma for the control chart.
Sample size	Specify the size of the sample from which the mean and standard deviation will be calculated for the Shewhart charts. This option is available only when either Shewhart Mean/Range or Shewhart Mean/Std is selected in the Properties drop-down list.
Minimum number of observations/sample	Specify the minimum number of observations that the sample must contain so that the mean or standard deviation will be calculated for the sample. This option is available only when either Shewhart Mean/Range or Shewhart Mean/Std is selected in the Properties drop-down list.