Specifications for Factor Grid
Click the Grid button on the GLM, GRM, or ANOVA Results dialog box - Profiler tab or the GLM, GRM, or ANOVA More Results dialog box - Profiler tab to display the Specifications for Factor Grid dialog box, in which you can specify the experimental range and the grid points for each of the predictor variables in the analysis. The combo box by the Grid button is used to specify the factor for which you want to specify grid points.
Use the Specifications for Factor Grid dialog box to specify the minimum value, the maximum value, and the number of intervals (steps) in the grid for the factor. These specifications determine the grid points for the factor, by setting the lowest grid point to the minimum value, the next lowest grid point to the minimum value plus the difference of the minimum value from the maximum value divided by the number of intervals, and so on up to the highest grid point. You can apply the same specification of number of intervals to all the predictor variables in the analysis by entering the desired number in the No. of steps field, and then clicking the accompanying Apply to all button. However, note that for categorical predictors, the specifications in this dialog box can only be set so that the grid points fall on the actual (observed) levels for the categorical predictor variables.
| Element Name | Description |
|---|---|
| << Prev., Next >> | Two methods are available for changing the factor for which you want to specify grid points without returning to the GLM, GRM, or ANOVA Results dialog box - Profiler tab or the GLM, GRM, or ANOVA More Results dialog box - Profiler tab. Click the << Prev. and Next >> buttons to cycle through the factors in the analysis in the reverse order, or order, respectively, in which they were selected to be included in the analysis. |
| Factor | You can also select a factor for which you want to specify grid points by selecting the factor from the Factor drop-down combo box. |
| Minimum | Enter the value (or use the accompanying microscrolls) that you want to use for the setting of the lowest grid point in the Minimum field. |
| Maximum | Enter the value that you want to use for the setting of the highest grid point in the Maximum field. |
| No. of steps | Enter the value that you want to use for the number of intervals in the grid in the No. of steps field. |
| Apply to all | Click the Apply to all button to apply the specification of number of intervals that has been entered in the No. of steps field to all the predictor variables (factors) in the analysis.
Note: specifying grid points. Grid points serve two functions in the
Profiler tab. They determine the plot points for the factors on the prediction profile compound graph and the surface and contour plots. They also determine the levels of the factors for which predicted values for the dependent variables are computed when the Optimum option button selected. Large numbers of grid points should be avoided when this option is used, to avoid unexpectedly long grid searches (see Response profiler options for details).
Note: grid points for categorical predictors variables. For categorical predictors, the specifications in this dialog can only be set so that the grid points fall on the actual (observed) levels for the categorical predictors variables. Also, in this dialog, the levels for the categorical predictor variable will always be referenced as consecutive integer values (e.g., 1, 2, 3), regardless of how the levels were coded in the data (e.g., Male = 101, Female = 102, Missing = -99; the Minimum value in this dialog is still 1, and the Maximum is 3).
See also GLM - Index. |