User Guide

Chapter 3

Random-Effect Priors. Uniform implies that all random effects and the residual term have

an equal impact on the observations. The

Zero scheme is equivalent to assuming zero

random-effect variances. Available only for the MINQUE method.

Sum of Squares. Type I sums of squares are used for the hierarchical model, which is

often used in variance component literature. If you choose

Type III, the default in GLM,

the variance estimates can be used in GLM Univariate for hypothesis testing with Type

III sums of squares. Available only for the ANOVA method.

Criteria. You can specify the convergence criterion and the maximum number of

iterations. Available only for the ML or REML methods.

Display. For the ANOVA method, you can choose to display sums of squares and

expected mean squares. If you selected

Maximum likelihood or Restricted maximum

likelihood

, you can display a history of the iterations.

Sums of Squares (Variance Components)

For the model, you can choose a type of sum 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.

The Type I sum-of-squares method is 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 polynomial regression model in which any lower-order terms are specified

before any higher-order terms.

 A purely nested model in which the first-specified effect is nested within the

second-specified effect, the second-specified effect is nested within the third, and

so on. (This form of nesting can be specified only by using syntax.)

Type III. This method, the default, calculates the sums of squares of an effect in the

design as the sums of squares adjusted for any other effects that do not contain it and

orthogonal to any effects (if any) that contain it. The Type III sums of squares have one

major advantage in that they are invariant with respect to the cell frequencies as long

as the general form of estimability remains constant. Therefore, this type is often