Specify fixed effects that are to be used to form interaction effects with the Exon (Probeset) ID Variable specified on the General tab. These are typically a subset of the Fixed Effects specified previously.
Distinct interaction effects are included in the model for each effect specified here. Significance of these interactions can be an indication of alternative splicing.
Caution: Specifying many effects here can result in an overspecified model and nonestimable LSMeans. In addition, specifying effects with many levels can greatly increase computing time, especially for transcript clusters that have numerous exons.
