## Statistical Science

### The $2\times2$ table: a discussion from a Bayesian viewpoint

J. V. Howard

#### Abstract

The $2\times2$ table is used as a vehicle for discussing different approaches to statistical inference. Several of these approaches (both classical and Bayesian) are compared, and difficulties with them are highlighted. More frequent use of one-sided tests is advocated. Given independent samples from two binomial distributions, and taking independent Jeffreys priors, we note that the posterior probability that the proportion of successes in the first population is larger than in the second can be estimated from the standard (uncorrected) chi-square significance level. An exact formula for this probability is derived. However, we argue that usually it will be more appropriate to use dependent priors, and we suggest a particular "standard prior" for the $2\times2$ table. For small numbers of observations this is more conservative than Fisher's exact test, but it is less conservative for larger sample sizes. Several examples are given.

#### Article information

Source
Statist. Sci., Volume 13, Number 4 (1998), 351-367.

Dates
First available in Project Euclid: 9 August 2002

https://projecteuclid.org/euclid.ss/1028905830

Digital Object Identifier
doi:10.1214/ss/1028905830

Mathematical Reviews number (MathSciNet)
MR1705267

Zentralblatt MATH identifier
1059.62526

Subjects
Primary: 62F15: Bayesian inference
Secondary: 62H17: Contingency tables

#### Citation

Howard, J. V. The $2\times2$ table: a discussion from a Bayesian viewpoint. Statist. Sci. 13 (1998), no. 4, 351--367. doi:10.1214/ss/1028905830. https://projecteuclid.org/euclid.ss/1028905830

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