Process Invariant Variables

Ribbon bar. Select the Data tab. In the Transformations group, click Filter/Recode and on the menu, select Process Invariant Variables to display the Process Invariant Variables dialog box.

Classic menus. On the Data - Data Filtering/Recoding submenu, select Process Invariant Data to display the Process Invariant Variables dialog box.

Use these options to specify the criteria for determining what variables are invariant.

Input. Use the options in the Input group box to specify the criteria for determining invariant data. Statistica uses this information to determine which variables should be removed from the data because of low (or no) variation.

Variables. Click the Variables button to display a standard variable selection dialog box used to select the variables to filter. The selected variables will be evaluated, and if the relative standard deviation is smaller than the value specified in the Relative Standard Deviation box, the variable will be removed.

Cases. Click the Cases button to display the Spreadsheet Case Selection Conditions dialog box, which contains options to select only specified observations or cases for the data filtering operation.

Relative Standard Deviation. Enter the minimum relative standard deviation to use in determining invariant variables. If a variables relative standard deviation is less than or equal to the number entered here, the variable will be removed from the data set. Relative standard deviation is calculated as the standard deviation divided by its mean (SD/X-bar).

Use Caseweights. Select this check box to use the currently assigned spreadsheet case weights in determining invariant variables. When this check box is selected, values of the case weight variable specified in the Spreadsheet Case Weights dialog box will be used as case multipliers before the invariant data processing is applied. If the check box is cleared, the assigned case weight will be disregarded for this analysis. Note that when case weights have not been assigned, this option is not available.

Output. Use the options in this group box to specify whether a new spreadsheet will be created and which variables (from the original data set) should be included in it. Note that when new spreadsheets are created, they will contain all variable properties of the parent spreadsheet, e.g., variable header formats, display formats, measurement types, etc. For more information on variable properties, see the variable specification dialog box topic.

Variables. Click the Variables button to display a standard variable selection dialog box used to select variables in the input spreadsheet that will be included in the output (filtered) spreadsheet.

Create new spreadsheet. When this check box is selected, Statistica creates a new spreadsheet that contains only the filtered data. If this check box is cleared, then invariant variables will be removed from the input spreadsheet.

Copy formatting. Select the Copy formatting check box to use the spreadsheet formats (e.g., cell formatting, variable header formatting, or even Spreadsheet Layouts) of the input spreadsheet in the output spreadsheet. When this check box is cleared, formatting in the input spreadsheet will not be copied to the new spreadsheet.

OK. Click the OK button to accept the options specified here and remove invariant variables from the current spreadsheet.

Cancel. Click the Cancel button to close this dialog without removing invariant variables from the current spreadsheet.