Cross - Validation

Click the Test sample button on either the Quick specs dialog box - Validation tab or the General C&R Trees Wizard Extended Options dialog box - Validation tab to display the Cross-Validation dialog box. This dialog box will also be displayed in the GLM, GLZ, GRM, PLS, GDA, ANOVA, and GCHAID modules.

Use this dialog box to specify a variable with a code to identify the observations that are to be included in the parameter estimation computations, i.e., in the fitting of the current model; the analysis sample comprises these observations. All observations that do not have the specified code value in the cross-validation variable will be excluded from the computations; however, you can compute predicted values and detailed residual statistics on the Results dialog box. If the excluded observations have valid data values for all predictor variables and dependent variables, the Cross-validation sample comprises these observations. (Note that the Prediction sample comprises observations that have valid data values for all predictor variables but missing data for one or more dependent variables in the current analysis.)

Sample Identifier Variable

Click the Sample Identifier Variable button to display a standard variable selection dialog box. Select the variable containing the code value (as specified in the Code for analysis sample field) to determine whether or not an observation belongs to the analysis sample.

Code for analysis sample

In this field, type in the code value (numeric or text) used in the Sample Identifier Variable to identify observations belonging to the analysis sample. Double-click in this field (or press the F2 key on your keyboard) to review all unique code (text) values in the currently selected sample identifier variable.

Status: On/Off

Select either the On or Off option button under Status to turn the selection of observations based on the Sample Identifier Variable on or off.

OK

After you are satisfied with the settings in this dialog box, click the OK button to close the dialog box and return to either the Quick specs dialog box - Validation tab or the General C&R Trees Wizard Extended Options dialog box - Validation tab.

Cancel

Click the Cancel button to close the dialog box and return to the either the Quick specs dialog box - Validation tab or the General C&R Trees Wizard Extended Options dialog box - Validation tab, ignoring any changes you have made in this dialog box.