7.5. Analysis of Variance (ANOVA)

These are notes by B. Douglas Ward, written in the Good Ol’ Days, and subsequently updated by Gang Chen.

7.5.1. Abstract

This document describes the programs contained within the AFNI distribution for performing Analysis of Variance on collections of 3-dimensional data sets. Specifically, programs 3dANOVA, 3dANOVA2, and 3dANOVA3 (for one, two and three factor Analysis of Variance, respectively) are described herein.

7.5.2. Program 3dANOVA

Purpose

Program 3dANOVA was developed to perform single-factor analysis of variance on collections of 3-dimensional data sets, voxel by voxel. As an extended program to 3dttest for two-sample t-test, 3dANOVA is usually used to test the effect of a condition across multiple groups. Through the command line inputs, the user specifies which data sets are to be used in the analysis, and to which factor level they belong. Various output options are available, including the F-test for equality of factor level means, estimation of individual factor level means, estimation of the difference btween two factor level means, andestimation of contrasts. The resulting outpu may be stored either as multiple AFNI 2 sub-brick datasets, or as a single AFNI “bucket” type dataset.

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7.5.3. ... Full Enlightenment

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