Model Browser User's Guide

Selecting Models

The Model Selection window appears when you click the Select... button. This window is intended to help you select a Best Model by comparing several candidate models.

The Model Selection window allows visual comparison of several models in many ways, depending on the type of model:

• Tests View
• Predicted/Observed View
• Response Surface View
• Likelihood View
• RMSE View
• Residuals View
• Cross Section View

Select

The Select button is under the list view in the pane at the bottom of the display. This pane is the Test Plans list pane at startup and changes title depending on the level in the model tree that is selected. The list box in this pane always contains the child nodes of whichever node in the tree is selected.

The pane also always contains three buttons: New, Delete, and Select.

Select is only available when the lower pane lists local models, response models, or models.

You can select among the following:

• Local models
• Response features
• Submodels of response features

But you cannot select between response models or test plans.

Note    To get a two-stage model at the response node, you must use the Select button at the local node (when the lower pane is the Response Features pane) to assign a model (even if it is the only one) as best. This step then calculates the two-stage model.

Select might not be available if you are not ready to choose among the child nodes. For example, at the response node, the child nodes must have models assigned as best (using the Select feature at those levels) before you can select among them. Also, if a response feature has child nodes of alternate models, you must select the best, or the Browser cannot tell which to use to calculate that response feature. After calculating MLE, Select compares the MLE model with the previous univariate model, and you can choose the best.

The Model Selection window allows visual comparison of several models. From the response level you can compare several two-stage models. From the local level, if you have added new response features you can compare the different two-stage models (constructed using different combinations of response feature models). If you have added child nodes to response feature models, you can compare them all using the Model Selection window.

When a model is selected as best it is copied up a level in the tree together with the outliers for that model fit.

A tree node is automatically selected as best if it is the only child, except two-stage models which are never automatically selected - you must use the Model Selection window.

If a best model node is changed the parent node loses best model status (but the automatic selection process will reselect that best model if it is the only child node).

Global Level: Menus

Model Selection Window