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Unformatted text preview: Lecture & Examples Topic 3: The Wilcoxon Signed Rank Test Introduction: The test presented in this lecture is known as the Wilcoxon Signed Rank Test. This test, presented by Wilcoxon (1945), is designed to test whether a particular sample came from a population with a specific median. It can also be used in paired difference experiments. For example, we are interested in comparing the twins with each other to see if the first- born twin tends to be more aggressive than the other. The Wilcoxon Signed Rank Test: Data: The data consists of n * observations on the respective bivariate random variables. Let |D i | = |X i- Y i | be the absolute differences for i = 1, 2, . . . , n *. Let n be the number of none zero differences. Assign ranks to these n absolute differences according to the relative size of the absolute differences. 1 Assumptions: (1) The sample of differences, D i , is randomly selected from the population of differences. (2) The D i 's are mutually independent. (3) The probability distribution for the sampled paired differences is continuous....
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- Spring '08
- Null hypothesis, Hypothesis testing, Statistical hypothesis testing, Statistical power, Wilcoxon Signed Rank