Bayes Factor Calculator

The following Bayes factor calculator replaces paired (one-sample) and groups (two-sample) t-test. Please see Rouder, Speckman, Sun, Morey and Iverson (2009) for details. We request that users of the calculator consider citing this paper. Bayes-factor calculations for cases with unequal variance and with one-tailed alternatives may be found at Ruud Wetzels' site.

More info/Questions: rouderj@missouri.edu


One-Sample Test
Replaces paired t-test.

The following application computes the BIC Odds, Jeffreys-Zellner-Siow Bayes factor, and unit Bayes factor for the one-sample test.

Sample Size:

t-value :

Scale r on effect size (optional, leave blank for default of 1.0):


Two-Sample Test
Replaced groups t-test

The following application computes the Jeffreys-Zellner-Siow Bayes factor and unit Bayes factor for the two-sample test.

Sample Size for Group 1:

Sample Size for Group 2:

t-value :

Scale r on effect size (optional, leave blank for default of 1.0):

Supported by NIH grant R01-MH071418 and NSF grant SES-0720229.
Updated 8/08.