These effects are modeled to explain variability in the principal components . Variance components are estimated for each effect and then combined into a single pie chart of total variability in the principal components.At least one variance component effect must be specified in order to produce results.For purposes of modeling additivity, all effects specified here are treated as random effects , even though you might normally consider them to be fixed effects in an ANOVA analysis.Effects typically contain one or more Class Variables , which must also be specified.

If you specify more than one effect, then you must separate the effects with spaces . For example, assuming A and B are listed as Class Variables , typing A B in the text field specifies variables A and B as main fixed effects.

To specify interactions between effects, type an asterisk ( * ) between the effects. For example, assuming A and B are listed as Class Variables , typing A B A*B specifies variables A and B , and the interaction between A and B as effects.

A vertical bar ( | ) can be used to create main effects and interactions. For example, typing A|B is the same as typing A B A*B .

An at-sign ( @ ) can be used to limit the number of interactions. For example, typing A|B|C@2 removes the three-way interaction term.