Analysis of Variance Package

This package provides functions for performing a univariate Analysis of Variance (ANOVA) to examine the differences between groups of means. The function ANOVA can handle models with any number of fixed factors in a crossed design. It can handle both balanced and unbalanced data with or without missing elements. All results are given as type I sums of squares. ANOVA also provides a number of post‐hoc tests for comparisons.

The ANOVA function.

The data must be of the form {{α₁,β₁,…,y₁},{α₂,β₂,…,y₂},…} where α_i, β_i, and so on are the values of the categorical variables vars associated with the i^th response, y_i.

The vars argument is a list of symbols representing the categorical variables in the model.

The model argument is a list of main effects and interactions that together specify the model. The interaction terms are given as the product of variables. For example, the full factorial model for a three‐way analysis of variance can be written as {α,β,γ,α β,α γ,β γ,α β γ}, where α, β, γ are the main effects, α β, α γ, β γ are the two‐way interactions, and α β γ is the three‐way interaction. Models can also be written using All to represent all main effects and interactions between the specified categorical variables. The full factorial model for a three‐way analysis of variance can therefore also be written as {α,β,γ,All}.

Options for ANOVA.

Available tests for the PostTests option.