ANOVA

For fixed effects models, certain properties can be stated for the two types of ANOVA. For the sequential ANOVA, the sums of squares are statistically independent. Also, the sum of the individual sums of squares is equal to the model sum of squares; which means the ANOVA represents a partitioning of the model sum of squares. However, some terms in ANOVA may be contaminated with undesired effects. The partial ANOVA is designed to eliminate the contamination problem but the sums of squares are correlated and do not add up to the model sums of squares. The mixed effects tests have similar properties.