User Guide

Linear Mixed Models

All 2-Way. Creates all possible two-way interactions of the selected variables.

All 3-Way. Creates all possible three-way interactions of the selected variables.

All 4-Way. Creates all possible four-way interactions of the selected variables.

All 5-Way. Creates all possible five-way interactions of the selected variables.

Build Nested Terms

You can build nested terms for your model in this procedure. Nested terms are useful

for modeling the effect of a factor or covariate whose values do not interact with the

levels of another factor. For example, a grocery store chain may follow the spending of

their customers at several store locations. Since each customer frequents only one of

those locations, the Customer effect can be said to be nested within the Store location

effect.

Additionally, you can include interaction effects or add multiple levels of nesting to

the nested term.

Limitations. Nested terms have the following restrictions:

 All factors within an interaction must be unique. Thus, if A is a factor, then

specifying A*A is invalid.

 All factors within a nested effect must be unique. Thus, if A is a factor, then

specifying A(A) is invalid.

 No effect can be nested within a covariate. Thus, if A is a factor and X is a covariate,

then specifying A(X) is invalid.

Sum of Squares

For the model, you can choose a type of sums of squares. Type III is the most

commonly used and is the default.

Type I. This method is also known as the hierarchical decomposition of the sum-of-squares

method. Each term is adjusted only for the term that precedes it in the model. Type I sums

of squares are commonly used for:

 A balanced ANOVA model in which any main effects are specified before any

first-order interaction effects, any first-order interaction effects are specified before

any second-order interaction effects, and so on.