User Guide

382
Chapter 22
Build Terms
For the selected factors and covariates:
Interaction. Creates the highest-level interaction term of all selected variables. This is
the default
.
Main effects. Creates a main-effects term for each variable selected.
All 2-way. Creates all possible two-way interactions of the selected variables.
All 3-way. C
reates 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.
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 for only 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.
 A polynom
ial regression model in which any lower-order terms are specified
before any higher-order terms.
 Apurelynestedmodelinwhichthefirst-specifiedeffectisnestedwithinthe
second-specified effect, the second-specified effect is nested within the third, and
so on. (Th
is form of nesting can be specified only by using syntax.)
Type II. This method calculates the sums of squares of an effect in the model adjusted
for all other “appropriate” effects. An appropriate effect is one that corresponds to all
effects t
hat do not contain the effect being examined. The Type II sum-of-squares
method is commonly used for:
 A balanced ANOVA model.
 Any model that has main factor effects only.