How to quantify support for and against the null hypothesis: a flexible WinBUGS implementation of a default Bayesian t test

Psychon Bull Rev. 2009 Aug;16(4):752-60. doi: 10.3758/PBR.16.4.752.


We propose a sampling-based Bayesian t test that allows researchers to quantify the statistical evidence in favor of the null hypothesis. This Savage-Dickey (SD) t test is inspired by the Jeffreys-Zellner-Siow (JZS) t test recently proposed by Rouder, Speckman, Sun, Morey, and Iverson (2009). The SD test retains the key concepts of the JZS test but is applicable to a wider range of statistical problems. The SD test allows researchers to test order restrictions and applies to two-sample situations in which the different groups do not share the same variance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bayes Theorem*
  • Bias
  • Data Collection
  • Data Interpretation, Statistical
  • Humans
  • Models, Statistical
  • Psychology, Experimental / statistics & numerical data*
  • Reproducibility of Results