Ratios-to-Moving Averages Classical Seasonal Decomposition (Census Method I)

Click the Seasonal decomposition (Census 1) button in the Time Series Analysis Startup Panel to display the Ratios-To-Moving Averages Classical Seasonal Decomposition (Census Method I) dialog box, which contains four tabs: Quick, Advanced, Autocorrelations, and Review series.

Use the options in the Ratios-To-Moving Averages Classical Seasonal Decomposition (Census Method I) dialog box to perform classical seasonal decomposition, a technique also known as the Census I method [see Seasonal Decomposition (Census I) for details; see also, Time Series Analysis Index].

Element Name Description
Summary: Seasonal decomposition Click the Summary: Seasonal decomposition button to display the Seasonal Decomposition spreadsheet. It is expected that you have 1) selected a variable to be analyzed (click in the Variable or Long variable (series) name column to highlight the variable (series) in the active work area), and 2) specified the Seasonal lag (length of seasonal period) or accepted the default value of 12 on the Quick tab.

To append any or all of the components that are computed to the active work area, set the respective check boxes in the On OK append components to active work area group box on the Advanced tab. If you choose to append components, make sure that there is sufficient "space" in the active work area for the respective variable, that is, that there are at least as many (not locked) backups available as there are components to be saved. Increase the Number of backups per variable (series) parameter (see below) if necessary. Also, be sure to Lock all important backups of the original variable (those which you want to retain); otherwise, those backups may be overwritten (refer to the section describing the memory management in the active work area). To lock a backup, double-click in the Lock column on the respective variable. In order to compute forecasts, use the Exponential smoothing facilities, which provide various options for computing forecasts based on additive or multiplicative seasonal models with or without trend.

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
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.
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 without performing any transformation and return to the Time Series Analysis Startup Panel.
Options Click the Options button to display the Options menu.