1. Note on the Cochran Q Test.
- Author
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Tate, Merle W. and Brown, Sara M.
- Subjects
- *
STATISTICAL correlation , *STATISTICS , *STATISTICAL sampling , *MATHEMATICS , *PROBABILITY theory , *MATHEMATICAL combinations , *STATISTICAL hypothesis testing , *MATHEMATICAL analysis , *LOGIC - Abstract
Cochran's Q test for differences between related-sample percentages or proportions has generally been incorrectly presented in secondary sources. The most common mistake results from failure to recognize that rows containing only 1's or only O's, i.e., only successes or only failures, do not affect the value of Q. The F test, however, is affected by such rows. The probabilities from the x[sup 2] and F approximations are compared with the exact probabilities in three sets of data. A rule of thumb, based on extensive study of the distribution of Q in small samples, is given as an aid in judging when the x[sup 2] approximation is satisfactory for practical purposes. [ABSTRACT FROM AUTHOR]
- Published
- 1970
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