Related Experiment Video
Updated: Dec 15, 2025

A Tactile Automated Passive-Finger Stimulator TAPS
Published on: June 3, 2009
Sample-size determination for the Bayesian t test and Welch's test using the approximate adjusted fractional Bayes
Qianrao Fu1, Herbert Hoijtink2, Mirjam Moerbeek2
1Department of Methodology and Statistics, Utrecht University, PO Box 80140, 3508 TC, Utrecht, The Netherlands. q.fu@uu.nl.
Abstract:
When two independent means μ1 and μ2 are compared, H0 : μ1 = μ2, H1 : μ1≠μ2, and H2 : μ1 > μ2 are the hypotheses of interest. This paper introduces the R package SSDbain, which can be used to determine the sample size needed to evaluate these hypotheses using the approximate adjusted fractional Bayes factor (AAFBF) implemented in the R package bain. Both the Bayesian t test and the Bayesian Welch's test are available in this R package. The sample size required will be calculated such that the probability that the Bayes factor is larger than a threshold value is at least η if either the null or alternative hypothesis is true. Using the R package SSDbain and/or the tables provided in this paper, psychological researchers can easily determine the required sample size for their experiments.
Related Concept Videos
Behrens–Fisher Test
This test...
Bonferroni Test
The means of different samples are first paired in all possible combinations.
The null hypothesis of the...
Testing a Claim about Mean: Unknown Population SD
Estimating a population mean requires the samples to be approximately normally distributed. The data should be collected from the randomly selected samples having no sampling bias. There is no specific requirement for sample size. But if the sample size is less than 30, and we don't know the population standard deviation, a different approach is used;...
One-Way ANOVA: Unequal Sample Sizes
Wald-Wolfowitz Runs Test II
For binary data, runs are identified using symbols such as + and −, or equivalently, 1s and 0s. In...
Comparing Experimental Results: Student's t-Test

