MARSplines Results - Plots Tab
Select the Plots tab of the Multivariate Adaptive Regression Splines (MARSplines) Results dialog box to access options to compute various 2D and 3D summary graphs to assist with the exploration and interpretation of results. In particular, the multiple scatterplots of specific predictor variables vs. predicted and observed values is very useful in order to fully understand the fitted model.
In general, select a single X variable, a list of Y variables, and a single Z variable; then select the desired graph(s). The Histogram option will compute a histogram for the selected X variable, the Graphs of X and Y option will compute simple or multiple scatterplots for the selected X variable vs. the selected list of Y variables, and the Graphs of X, Y, and Z option will fit surface plots to the triplets of selected variables in X, Y, and Z.
| Element Name | Description |
|---|---|
| Select dependent variable(s) | Click this button to display a standard variable selection dialog box, in which you select the dependent variables for which to compute the graphs; separate results graphs will be computed for each dependent variable. |
| X-axis | For all plots, select the type of predicted value, residual value, or variable in the X-axis list. |
| Y-axis | For plots requiring two or more variables (scatterplots, surface plots), select an additional type of predicted value, residual value, or variable in the Y-axis list. |
| Z-axis | For plots requiring three variables (i.e., surface plots), also make a selection from the Z-axis list. |
| Histograms of X | Click this button to display a histogram for the variable, type of predicted values, or residual values, as selected in the X-axis list. |
| Graphs of X and Y | Click this button to display a scatterplot for the variables, type of predicted values, or residual values, as selected in the X-axis and Y-axis lists. This option is particularly useful for displaying the results for a single predictor variable (selected as the X-axis variable) vs. the predicted and observed values (selected into the list of Y-axis variables). |
| Graphs of X, Y and Z | Click this button to display a surface plot for the variables, types of predicted values, or residual values, as selected in the X, Y, and Z-axes lists. |
| Include case names | Select this check box to include case names on the graphs. |