Transformations of Variables

Click the OK (transformations, autocorrelations, crosscorrelations, plots) button in the Time Series Analysis Startup Panel to display the Transformations of Variables dialog box, which contains nine tabs: x=f(x), Smoothing, x=f(x,y), Shift, Difference, integrate, Fourier, Review & plot, Autocorrs, and Descriptives.

OK (Transform selected series). Click the OK (Transform selected series) button to transform the variable (series) that is selected in the active work area. Transformed variables will be appended to the active work area. The number of backups that will be kept for any one variable is determined by the Number of backups per variable (series) parameter (see below). If a transformation produces an invalid value (e.g., square root of a negative value, division by zero, etc.), STATISTICA will assign a missing data value; then, in a second pass, those missing data will be replaced according to the choice in the Time Series Analysis Startup Panel - Missing Data tab.

Active work area. The Active work area is composed of three columns: Lock, Variable, and Long variable (series) name. For detailed information on the Active work area, see Time Series Analysis - Active Work Area.

Lock. Double-click on a transformed variable in the Lock column to lock or unlock the variable in the active work area. An L is listed in the column to indicate that the variable is locked. Locked variables will not be replaced as successive transformations exceed the current maximum number of backups. Note that original (untransformed) variables are always locked, and they cannot be unlocked. For more information, see Active Work Area.

Variable. The Variable column contains the short name of the variable(s) currently available for analysis. Click on a variable name in the list to highlight that variable (series) in the Active work area that is to be analyzed For more information, see Active Work Area.

Long variable (series) name. When a new (e.g., transformed) variable is appended to the active work area, the Long variables (series) name column will display a new long variable name that consists of the old long variable name (as much of it as will fit) and a brief description of the respective transformation that was performed. For more information, see Active Work Area.

Number of backups per variable (series). The parameter entered in the Number of backups per variable (series) box determines the maximum number of backups (i.e., previous versions of the series) that is kept in the active work area for each variable. After a transformation (or other analysis) is performed on a series, the resulting transformed series (or residuals, forecasts, etc.) will be appended to the active work area, and the values of the series prior to the transformation will be maintained as a backup. When a new transformation is appended and the maximum number of backups for the respective original variable is exceeded, the "oldest" previous backup will be replaced. You can lock a variable (prevent it from being overwritten) by double-clicking on the respective variable in the Lock column. For more details, refer to Active Work Area.

Save variables. Click the Save variables button to save the variables (series) that are currently available in the active work area into a standard STATISTICA data file (which can be used as input for subsequent analyses).

Delete. Click the Delete button to delete the currently highlighted variable. To highlight a variable, click on it either in the Lock, Variable, or Long variable (series) name column.

Cancel. Click the Cancel button to close the dialog box without performing any transformation and return to the Time Series Analysis Startup Panel.

Options. Click the Options button to display the Options menu.

By Group. Click the By Group button to display the By Group specification dialog box.