All Questions
Tagged with nonparametric wilcoxon-mann-whitney-test
176
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Can I use Mann-Whitney U test for within group analysis?
I am conducting a within-group study where participants rate the perceived helpfulness of ideas on a Likert scale (DV) across two different days (Day 1 and Day 2), serving as the independent variable (...
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9
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Basic question regarding before and after intervention analysis on groups of different sample size
Apologies for the basic nature of this question. I have collected data before and after an intervention and assessed response to the intervention using a survey. This was a basic survey using a 1-5 ...
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2
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161
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Parametric vs Non-parametric test recommendation
What type of non-parametric test would be suitable for the dataset shown in the image:
The sample size is 200 each for both variables. The data value can vary from 0-4 for both variables. The ...
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528
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How to deal with negative values after subtracting the background?
I am working with Luminex data and have a question regarding the treatment of negative values after subtracting the background average. Specifically, I would like to know if these negative values need ...
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207
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Kruskal-Wallis returns only one significant group (out of 4 groups), when significant group is removed and test redone, another group is significant?
I am comparing 4 groups of samples using SPSS. The groups are 4 bathymetry groups (>0m, >-1m, >-2m, >-3m). Within each group are a number of samples n. Each sample has a recorded seagrass ...
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96
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Is there an optimality result for the two-sample Wilcoxon-Mann-Whitney test?
Is there any mathematical result that states that the Wilcoxon-Mann-Whitney (WMW) test is optimal in some sense, for a specific testing problem that is a subproblem of the general problem the WMW test ...
- 26k
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419
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How is the Mann Whitney U test statistic derived?
The t-test statistic is derived from the CLT and allows for some probabilistic statements to be made.
$$ U_1 = n_1(n_1+1)/2 + n_1 n_2 - R_1 .$$
I know the test does not assume a probability ...
- 741
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95
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Common language effect size / Probability of Superiority with Measurement Error
The setting is comparing two independent groups represented by random variables $X$, and $Y$. The common language effect size / probability of superiority / relative effect ... is defined as $p(X,Y)=P(...
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675
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Small sample size: Permutation test or Wilcoxon test?
What do you think about using a permutation test each time the sample size is too small to meet the the assumptions of normality and homogeneity of variance etc ? Why do we use a non parametric ...
- 579
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555
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Which non-parametric test should I use to compare 2 independent groups when i have several ties (Wilcoxon not good for this weird sample)?
I'm doing an analysis of a master's student in which I need to compare a continuous numerical variable between two groups. The samples are independent and each group contains only three observations ...
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131
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Alternative for Wilcoxon Test?
I'm ending my Master's Thesis, and I'm trying to figure out which test to use to calculate the significance of my data.
Basically, we measured the Free Kick biomechanical parameters of several ...
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173
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Can the Mann-Whitney test be used to analyze two different Likert scale questions answered by the same users?
Can the Mann-Whitney test be used to analyze two different Likert scale questions answered by the same users before and after an experiment? For example, question 1 is asked before doing an experiment ...
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188
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How to conduct a boostrapped or a permutation wilcoxon test (in R)
I have a total of 18 mice, 9 from Healthy group and 9 from Sick group. Since I have a very poor sample size I would like to use boostrapping or permutation test.
Is there a way to conduct a ...
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2k
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How to handle ties in pairwise wilcoxon rank-sum test?
I am willing run the wilcoxon rank sum test for different combination of variables, and using the base R code, I get a lot of warnings. The reason is that there are so many (about 30% of the whole ...
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234
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Wilcoxon Rank Sum test - appropriate to compare frequency of events between two sources?
I have some data on the frequency that a particular claim is referenced by two distinct types of sources. The first is traditional news media, and the second source are conspiracy theory sites. I want ...
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