Model Browser User's Guide

Global Model Class: Multiple Linear Models

The preceding example shows the defaults for multiple linear models. You can add linear models (as seen in the single linear model settings).

This is primarily for designing experiments using optimal designs. If you have no idea what model you are going to fit, you would choose a space-filling design. However, if you have some idea what to expect, but are not sure exactly which model to use, you can specify a number of possible models here. The Design Editor can average optimality across each model.

For example, if you expect a quadratic and cubic for three factors but are unsure about a third, you can enter several alternative polynomials here. You can change the weighting of each model as you want (for example, 0.5 each for two models you think equally likely). This weighting is then taken into account in the optimization process in the Design Editor.

The model that appears in the model tree is the one you select, listed as Primary model. Click the model in the list, then click Use Selected. The Primary model changes to the desired model. If you do not select a primary model, the default is the first in the list.

When the model has been fitted, you can view the primary model at the global node. To compare the fit of all the alternatives, click Build Models in the toolbar, select Multiple Linear Models in the dialog, and click OK. One of each model is then built as a selection of child nodes.

See also Polynomials.

Global Model Class: Hybrid RBF

Global Model Class: Free Knot Spline