The Appropriateness of Some Common Procedures for Testing the Equality of Two Independent Binomial Populations |
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Authors: | Ralph B. D'agostino Warren Chase Albert Belanger |
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Affiliation: | 1. Mathematics Department , Boston University , Boston , Massachusetts , 02215 , USA;2. Mathematics Department , Framingham State College , Framingham , Massachusetts , 01701 , USA;3. Statistics and Consulting Unit, Boston University , Boston , Massachusetts , 02215 , USA |
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Abstract: | For testing the equality of two independent binomial populations the Fisher exact test and the chi-squared test with Yates's continuity correction are often suggested for small and intermediate size samples. The use of these tests is inappropriate in that they are extremely conservative. In this article we demonstrate that, even for small samples, the uncorrected chi-squared test (i.e., the Pearson chi-squared test) and the two-independent-sample t test are robust in that their actual significance levels are usually close to or smaller than the nominal levels. We encourage the use of these latter two tests. |
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Keywords: | Fisher exact test Ill-use of the continuity correction Robustness of the t test Small sample testing |
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