AUTHOR=Fu Qianrao , Moerbeek Mirjam , Hoijtink Herbert 

TITLE=Sample size determination for Bayesian ANOVAs with informative hypotheses

JOURNAL=Frontiers in Psychology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2022.947768

DOI=10.3389/fpsyg.2022.947768

ISSN=1664-1078

ABSTRACT=<p>Researchers can express their expectations with respect to the group means in an ANOVA model through equality and order constrained hypotheses. This paper introduces the <monospace>R</monospace> package <monospace>SSDbain</monospace>, which can be used to calculate the sample size required to evaluate (informative) hypotheses using the Approximate Adjusted Fractional Bayes Factor (AAFBF) for one-way ANOVA models as implemented in the <monospace>R</monospace> package <monospace>bain</monospace>. The sample size is determined such that the probability that the Bayes factor is larger than a threshold value is at least η when either of the hypotheses under consideration is true. The Bayesian ANOVA, Bayesian Welch's ANOVA, and Bayesian robust ANOVA are available. Using the <monospace>R</monospace> package <monospace>SSDbain</monospace> and/or the tables provided in this paper, researchers in the social and behavioral sciences can easily plan the sample size if they intend to use a Bayesian ANOVA.</p>