Questions tagged [wilcoxon-signed-rank]

Wilcoxon signed-rank test is a non-parametric rank test to compare two paired samples, whether values in one are bigger than in the other. Can also be used to compare one sample to a fixed value. [The test NOT to be confused with the `sign-test`].

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Hypothesis testing with regression models

I have two regression models: a linear model with one variable, and a neural network with many. I want to test whether the neural network is better than the linear model. I am wondering the best way ...
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How to merge multiple one-sample Wilcoxon-tests into single test/model

I have data on the monthly rent of a certain group of people (n = 10 people). We call them people X. These people live in different neighborhoods (very far apart). Furthermore, I have data on the ...
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Wilcoxon signed rank with multiple repetition

How could I do Wilcoxon signed-rank statistical significance test with multiple replications in python or other languages? (since python does not have any parameter as the input of the function for ...
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71 views

Analyzing ABn test when normality is not met

I'm analyzing an unpaired A/B/C/D test to assess whether the mean or median of population B/C/D is higher than the one of A. As shown from the left plot the normality distribution cannot be assumed. ...
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36 views

paired test VS unpaired test

I have a set of paired measurements which were collected before and after some trigger for a set of users. Users can react differently to trigger, i.e for some measurements before trigger are larger ...
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Treatment of Ties in sign test (paired-samples sign test)

I'm curious about the validity of removing/ignoring ties when calculating the p-value for the sign test. By ties I mean ($x_{before} = x_{after}$, where $x$ represents the measurement). According ...
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What Wilcoxon Test is appropriate for paired categorical data?

There is currently a story in the news in the UK about negative effects of puberty blockers in children: 'It showed that after a year on puberty blockers, there was a significant increase found in ...
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Why several studies change logical paired/unpaired assumption from omnibus to post-hoc?

There are several studies of highly-referenced researchers where a paired post-hoc test (e.g. Wilcoxon signed-rank) follows the omnibus unpaired test (e.g. Kruskal-Wallis): From Huang et. al "THE ...
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Test for multiple samples of ordinal data

I have 10 independent samples of ordinal data ranked 1-3. I also have predicted ranks for the same data set. I want to test if the predicted ranking matches the observed ranking at a rate better ...
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Kolmogorov-Smirnov test vs. Wilcoxon signed-rank test for two samples

I would like to ask a question about the usage of Kolmogorov-Smirnov test and Wilcoxon signed-rank test to show that two samples have the same distribution (specifically, log-normal). Specifically, I ...
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279 views

Wilcoxon signed rank test – critical value for n>50

I have seen that someone has asked a similar question a few years ago, but unfortunately the answer is not helpful. I am in the process of estimating a Wilcoxon signed rank test with a n=63 by hand. ...
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Compare change of ordinal variables between admission and dismission with different levels

I would like to compare difference between admission and dismission fron rehab center of an ordinal variable relative to diagnosis. At admission patients are divided in 3 groups (Emersion, SMC or SV, ...
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Wilcoxon signed rank test?

I would appreciate any advice possible. I am doing a study to look at change in value of my markers before and after a device change. My data is non-normal. I need to see how the value changes from ...
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In R (nlme/lme4), how do I compare two linear models with different sample sizes and different groups? [duplicate]

First off, I have a dataset with sparse longitudinal data. There are 30 individuals with 1 sample, 30 individuals with 2 samples, and 5 individuals with 3 samples. Various categorical variables are ...
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Statistical test for rubric-scored student responses

I am generally a qualitative researcher, but in my current study I am asking a research question that requires (very little, but some) quantitative tools. Simplistically, I have scored students' ...
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mutation difference

I am hematology/oncology physician. i am doing project in CNS lymphoma. i have a question about the best method to calculate if there is any statistical difference in mutation frequencies between 2 ...
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Potential problem in using paired t-test or Wilcoxon if the two samples consist of multiple draws from same group?

I have an experiment that works loosely works as follows: There are ten subjects in each treatment. There are two treatments, A and B. Each treatment has 8 rounds. In each round, each subject is ...
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Comparing the performance of two algorithms with Wilcoxon Signed-Rank Test

I have two algorithms A and B which have to compute a solution to some problem. Each solution is given some objective value ...
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Wilcoxon signed rank test - interpretation

I have 6 dependent variables that were measured on a 5 point Likert scale (treated as interval here). I want to test if their means differ significantly from the midpoint 3. As the normality ...
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Is my interpretation for Wilcoxon Signed Rank test correct?

I ran a wilcoxon signed rank test on paired samples where the outcome variable was a test score. The samples were paired by as siblings (younger and older sibling). I have a problem interpreting the ...
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How does Normal approximation work when ties exist for Wilcoxon Signed rank test?

I ran wilcox.test() in R (outcome variable was a test score and the data was paired samples) and got a warning message saying that it cannot generate a p-value for tied values. I saw the R document ...
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Pseudo median from Wilcoxon signed rank test larger than sample median?

I am left wondering, why I can be in a situation where the pseudo median (population estimator) of a Wilcoxon signed rank test, can be larger than the simple differences between sample medians? I am ...
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Paired or unpaired t-test and Wilcoxon signed rank test?

I am having a conceptual problem, of not being able to grasp whether my data is paired or unpaired. I have to test for the mean and median differences between two sets of data: SBP and GICS (see ...
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Wilcoxon rank signed test, paired or non-paired test?

I have been trying to figure out, whether or not I should use a paired or a non-paired test. My question comes from the fact, that I am trying to get the pseudo median, in order to say that SBP is [x] ...
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108 views

Wilcoxon signed rank test - help on interpretation of pseudo median

I am performing a Wilcoxon signed rank test in R, for two paired samples, where I have used the following: ...
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Wilcoxon signed rank test, getting a numerical media difference instead of p-value?

I have been running the Wilcoxon signed rank test, where my output is a p-value. Now, the p-value interpretation I am confident in, but I read in a paper that the authors reported the: The Wilcoxon ...
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60 views

Bonferroni for Wilcoxon signed rank?

I conducted a survey that asked participants to rate their level of agreement on a 5 point Likert scale with nine items (1=strongly agree, 5=strongly disagree). Hence, a mean score of 3 would mean ...
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Paired samples with various ordering in observations, signed rank test?

I have a small number (10) of samples to analyze The idea is to measure the impact of two surgical procedures, A and B. In my population, I have people who did first A, and then B, and other people ...
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Wilcoxon - one sample abnormal stock returns

I got a dataset with abnormal stock returns for around 400 securities and i need to find out if they're statistically different from zero. They don't follow a normal distribution, so i would like to ...
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78 views

Wilcoxon signed-rank test for paired and repeated measures data

I have a dataset with 45 participants, each with 1-7 datapoints/observations (126 total observations). Each of these observations represents a window of time in which two different methods attempt to ...
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Paired Wilcoxon signed rank test-compare median

I have been comparing driving behavior before and after a technological intervention for a specific group of people. My data is far from normal hence I have used paired Wilcoxon signed rank test. If ...
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59 views

Can a Wilcoxon signed rank test be applied on dated data?

I have data for military male and female orders for types of clothing purchased from 2012 to 2018 (below is a very simple example - most of the data is one item purchases). If I look at one type of ...
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142 views

P-Values in Wilcoxon test

I have a question that if a p value less than 0.05 in wilcox test means that the two data are significantly different and the p-value of 1 means that are exactly same, then what is the meaning of a p-...
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Is it correct that JMP has Mann-Whitney U for comparing more than 2 unpaired groups (instead of Kruskal-Wallis)?

To the best of my knowledge, the Mann-Whitney U test (also called Wilcoxon-Mann-Whitney) is for comparing only two unpaired groups, while the Kruskal-Wallis test is used for comparing two or more ...
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How do you perform Wilcoxon matched-pair sign-rank test in Stata using a grouping variable? [closed]

I'm performing a diagnostic method comparison study in which I have 2 groups; one assessed using the experimental method, and one assessed using the standard method. These groups are matched, with 3 ...
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Violating the assumptions of one sample t-test and wilcoxon's sign test

As far as the background of my research is concerned, I developed a framework for sustainability management in organizations through a systematic review of literature and sustainability reports. That ...
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26 views

Comparing changes in pre-post count results for two cohorts

Thanks in advance! I have a pre-post analysis Of cases and controls. The outcome variables of interest are emergency room visits and hospitalization visits - both rare occurrences with median = 0 ...
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1answer
56 views

How to run Friedman test correctly across three sets of questionnaire data divided into sub-groups?

I am trying to evaluate the usability of three prototypes of an application and want to see if there is a significant difference in terms of usability. For this I have collected responses from users ...
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Post hoc for wilcoxon multiple tests

I have a database of brain MRI acquisitions of 20 subjects at two time points. I have elaborated the signal with multiple models. For each model, I have estimated 4-6 parameters maps. At the moment I ...
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1answer
45 views

Different results from wilcoxsign_test - which test to use?

I am running a wilcoxsign_test from the coin-package and I get different results depending on whether I split my data or not. My data is a data.frame with 3 columns: "Proband", "Treatment", "Mdev". ...
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How to remove pair-wise comparisons that are affected by a batch covariate in pairwise Wilcoxon test

I have a dependent variable that is grouped by an independent.variable (with 3 factor levels) and I want to calculate pairwise comparisons between the groups of the independent.variable. However, I ...
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NASA TLX Analysis

I am trying to analyze a NASA TLX. The NASA TLX is the de facto standard for subjective workload task load. In my experiment (n=27), participants drove a track in a driving simulator while ...
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Imposing orders on distributions based on Wilcoxon test

I am trying to figure out part of a text I am reading about non parametric tests. In there it is stated that: The fact that the output of a rank test is driven by the probability that a value ...
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166 views

Wilcoxon Signed Rank Test in Python (Reporting Siegel's T vs W?)

While using the Wilcoxon signed rank test in scypy over a subset of populations, I noticed that my test score was reported as zero for an array of differences whose distribution of medians is heavily ...
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392 views

R: coin::wilcoxsign_test() distribution = “exact”

In a repeated measure design, I have two measurements for one variable for N=5 subjects. I am interested in assessing whether the distribution of the differences between the two measurements is ...
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One-tailed test for comparing paired dichotomous responses

Given reference samples $R_i$, I have two dichotomous responses $X_i$ and $Y_i$ I wish to compare. Each dichotomous response (relevant vs. irrelevant to the reference $R_i$) is generated by an ...
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How do I report a Wilcoxon-signed rank test if the medians are the same?

I have data comparing 2 likert-scale answers (1 to 7) where the p<0.05 but the medians are the same. I'm trying to report this in a table. My instinct was to report this similar to a t-test, with ...
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1answer
591 views

How to graph Wilcoxon test power R

I've been trying to calculate and graph the correspondent power for the wilcoxon signed test and haven't had any luck. I tried simulating two normal distributed samples, apply the wilcoxon test and ...
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Wilcoxon test with multiple testing: which correction for p values?

Please, I'm not very confident in statistics, and I'm trying to respond to a reviewer for a paper on the following issues: In my experiment I observed 15 babies during a test where they were free to ...
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349 views

Interpretation of the t.test and Wilcox.test in R

I got two distribution which are not pairs. It's difficult to say that they are also from a normal distribution because they have different length. The distributions of the vectors are, for gas: <...