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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True
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False
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Either A or B
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None of the above
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Detailed explanation-1: -Wilcoxon rank-sum test is used to compare two independent samples, while Wilcoxon signed-rank test is used to compare two related samples, matched samples, or to conduct a paired difference test of repeated measurements on a single sample to assess whether their population mean ranks differ.
Detailed explanation-2: -The next step of the Wilcoxon sign test is to sign each rank. If the original difference < 0 then the rank is multiplied by-1; if the difference is positive the rank stays positive. For the Wilcoxon signed rank test we can ignore cases where the difference is zero. For all other cases we assign their relative rank.
Detailed explanation-3: -Dealing with ties: There are two types of tied observations that may arise when using the Wilcoxon signed rank test: Observations in the sample may be exactly equal to M (i.e. 0 in the case of paired differences). Ignore such observations and adjust n accordingly.