METHODS OF DATA ANALYSIS
PARAMETRIC AND NON PARAMETRIC TESTS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Wilcoxon
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Kruskal-Wallis
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Mann-Whitney
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Friedman
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Detailed explanation-1: -Typically, a Kruskal-Wallis H test is used when you have three or more categorical, independent groups, but it can be used for just two groups (i.e., a Mann-Whitney U test is more commonly used for two groups).
Detailed explanation-2: -There are differences in the assumptions and the hypotheses that are tested. The ANOVA (and t-test) is explicitly a test of equality of means of values. The Kruskal-Wallis (and Mann-Whitney) can be seen technically as a comparison of the mean ranks.
Detailed explanation-3: -The Kruskal–Wallis test is just the rank-sum test extended to more than two samples. Think of it informally as testing if the distributions have the same median. The chi-square (2) approximation requires five or more members per sample. Name the number of samples m (3, 4, …).