Random Forest
On the Model building tab, select the Random forest check box and click the Random forest button to display this dialog box.
| Element Name | Description |
|---|---|
| Number of trees | Specify the number of simple regression trees for computing in successive forest building steps. |
| Minimum number to stop | Specify the minimum number of cases in a terminal node.
One way to control splitting is to allow splitting to continue until all terminal nodes contain no more than a specified minimum number of cases or objects. |
| Minimum child node size to stop | Controls the smallest permissible number in a child node, for a split to be applied.
While the Minimum number to stop parameter determines whether an additional split is considered at any particular node, the Minimum child node size to stop parameter determines whether a split is applied, depending on whether any of the two resultant child nodes are smaller (have fewer cases) than n as specified through this option. |
| Maximum number of levels | Specify the value for stopping on the basis of the number of levels in a tree.
Each time a parent node is split, the total number of levels (depth of the tree as measured from the root node) is examined, and the splitting is stopped if this number exceeds the number specified in the Maximum number of levels box. |
| Maximum number of nodes | Specify the value for stopping on the basis of the number of nodes in each tree.
Each time a parent node is split, the total number of nodes in the tree is examined, and the splitting is stopped if this number exceeds the number specified in Maximum number of nodes box. The default value 3 causes each consecutive tree to consist of a single split (one root node, two child nodes). |
| Prior probabilities | Specify without using any prior knowledge of the values for the predictor variables in the model, that a case or object falls into one of the classes.
Select Estimated from the drop-down list to specify that a case or object falls into one of the classes and is proportional to the dependent variable class sizes. Select Equal from the drop-down list to specify that a case or object falls into one of the classes and is the same for all dependent variable classes. |