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Questions tagged [wilcoxon-signed-rank]

a non-parametric rank test to compare two paired samples, whether values in one are bigger than in the other. This test is NOT the same as the sign test.

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Statistical test for unequal sample sizes of repeated measures (non-parametric)

I'm looking to understand the differences between various sources (50) that evaluate an event based on 8 ordinal scales (varying from 2 to 4 values) associated with a discrete score between 0 and 10, ...
ron's user avatar
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2 votes
1 answer
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Can Wilcoxon signed rank test be used with sample size of 4 paired data sets?

My Project compares pre-test and post-test ratios in addition to pre-test and past-test Likert scale. I planned to use Wilcoxon signed rank. I only have a sample size of 4. Can I still use Wilcoxon ...
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what is the meaning of “One-sample test.”?The following is clearly a two-sample test for wilcox.test

The code that inspired this question can be found here and below: ...
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Can Wilcoxon be used in large sample with non-normal distribution?

I am doing my undergrad research, aiming to know the difference of before and after an intervention. our sample size is 37 which is already considered as a large sample right? However, when we test ...
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Wilcoxon signed rank test in QI macros

I need some help in understanding the wilcoxon signed rank test. I am using this test on comparing two analysers. We ran the same samples on two analysers for the PT (prothrombin time), the results ...
Haha Blues's user avatar
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How should I analyze data that is paired and also repeatedly measured?

I have data collected from the same subjects (n=10) over 11 days, with measurements taken under two conditions each day: immediately after training(D0) and 30 minutes after training(D30). The data is ...
benrilzm's user avatar
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Wilcoxon Sign Rank Test with differing list lengths [closed]

I am running a Wilcoxon Sign-Rank test with two lists. One contains 5 elements and the other contains 6. They were taken from the same place but under different conditions. I am trying to compute the ...
Indefeasible's user avatar
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Questions about equivalence hypothesis testing

The setup for the current question is the same as a previous question of mine, with one important difference: I have decided to go for a paired test, by always performing two consecutive experiments ...
swineone's user avatar
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3 answers
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Wilcoxon Signed rank test for heavily tied paired data

We conducted an experiment to test the effect of a map annotated with the height of landscape features on participant's estimates of height relative to that recorded by a UAV. We asked them to record ...
Nicola 's user avatar
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Comparing the ranking of effect sizes?

I have a lot of effect sizes, estimated from the same linear model, but where the tested explanatory variable is different. These models are run in two different groups, but it is the same model and ...
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Wilcoxon's Signed-Rank Test in the context of 2 algorithms and 1 domain

I'm trying to understand whether my analysis for a problem is in the right direction. I have 2 algorithms (3d object detectors) that I've applied to the same dataset to obtain TP, FP and FN's for each ...
neoavalon's user avatar
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How to compare semi-independent groups?

I need to compare the answers to a questionnaire (pre / post). The questionnaire was designed using a Likert scale. The two groups were made up of populations, some of whom were in both groups but ...
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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 (...
JBUG's user avatar
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Test for statistically significant difference: Wilcoxon vs Median Permutation

I have a dataset that shows measured 'perceived quality'(dependent variable), by two different sizes in the context of 4 different intensity levels (200 values for perceived quality in each category, ...
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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 ...
june2023's user avatar
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What do these Wilcoxon values tell me?

I did a pre and post-test with a small number of students ($n=12$).These values came after a science intervention that took $4$ weeks. I used a Wilcoxon test for 2 related samples as there was not a ...
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Wilcoxon test on distribution derived from bootstrapping

We have two Chocolate bags X and Y. Each chocolate bags have total 1000000 chocolate boxes randomly sampled from 100 types of chocolate boxes (B1, B2, …, B100). These chocolate boxes are of different ...
jayesh kumar's user avatar
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1 answer
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Paired t-test on dependent samples

I have a set of paired observations, corresponding to patient blood pressure before and after a treatment. I'd like to test for the significance of the treatment by conducting a paired t-test (or ...
Smoked_Carp's user avatar
2 votes
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Kruskal-Wallis Test shows significance, but Pairwise Wilcoxon Rank Sum Test does not

I used the following code to perform a Kruskal-Wallis test on a dataset, which gave me a significant p-value (5.159e-06). However, when I then use pairwise.wilcox.test() to perform a Pairwise Wilcoxon ...
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simulate the number of samples to be statistic relevant using a non-paremetric paired test

I have an experiment where a group of subjects must learn to associate some sounds to images (say, sound 1-image 1, sound2-image 2,... soundN-imageN). They do a memory test (we present sounds and ...
user3284182's user avatar
3 votes
2 answers
238 views

Transitivity of Wilcoxon signed-rank test

I have performed Wilcoxon signed-rank tests for variables $X$, $Y$, and $Z$, where it appears that (speaking informally) $X < Y < Z$. Indeed, the p-value for the one-sided Wilcoxon signed-rank ...
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Multiple testing with Wilcoxon signed rank test with set maximum length

I'm essentially performing this test with the Java Apache math3 method which only allows lengths up to 30. My pairs will have a length of maximum 2048. I will be testing for an increase (combination ...
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investigation of a potential change of measured values: only the simple linear regression or also compare the mean of follow-up values with baseline?

For my medical dissertation I am studying a group of 36 patients. The patients received a drug repeatedly over several months. Serum levels of two cytokines were measured in the patients both before ...
Katharina's user avatar
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1 answer
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Validity of Wilcoxon Signed Rank or Spearman for 2 Likert Scales

I am working on my MSc dissertation findings and I have data results from two 5-Point Likert scales. One Likert measured self-assessed behaviour, whilst the other measured attitude. (Both scales were ...
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Test(s) for comparing predictor quality for different features?

I applied a predictor to different numeric features from the same group of subjects (n>1000). The features have different ranges. Is it possible in this case to apply a statistical test to make a ...
user1448268's user avatar
7 votes
3 answers
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Questions about Wilcoxon signed rank test

I wanted to conduct a Wilxocon signed rank test but stumbeld upon two questions that I am unable to solve on my own. I tested 2 types of interfaces for a software with the same ten people. I want to ...
Lukas Pezzei's user avatar
2 votes
0 answers
57 views

Zero differences and Wilcoxon signed rank test

I am wondering if the Wilcoxon signed rank test is an appropriate test for my data, that does not follow a normal distribution. I have 150 datasheets of numbers of drugs measured at two points in time....
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1 vote
1 answer
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Constant p-value for all my tests

I am comparing the performance of two AI models across 15 data sets. One model performs heavily better than the other on all the performance metrics. When I perform a one-tailed Wilcoxon signed rank ...
M Germanos's user avatar
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2 answers
62 views

Two sample t-test vs One-sample t-test on residuals [closed]

For some arbitrary data, I have the raw data and a fitted model (not a regression model, but more so a model that accounts for noise and imperfections the data acquisition). I want to see how closely ...
Bodhi's user avatar
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Analysing pre and post intervention MCQ results for significance- which statistical test to use?

I have ran a teaching course for students. I carried out pre and post session MCQ quizzes to evidence effectiveness of the course, however the marks collected were anonymised (data collected via ...
S Hussain's user avatar
5 votes
1 answer
184 views

Calculation of standard deviation of the mean changes from the p-value or z-value of the Wilcoxon test

I am conducting a meta-analysis of observational studies without a control group that compared a parameter's value before and after an operation. All included studies have reported their results as ...
victor james's user avatar
3 votes
1 answer
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What exactly does the “symmetric distribution” assumption of the Wilcoxon signed-rank test refer to? [duplicate]

I have two lists (or sets) of data that I would like to statistically compare. More precisely, I would like to check if the difference between data list one and data list two is statistically ...
Philipp's user avatar
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Determining KAP assessment post-intervention significance: use a paired t-test, signed-rank Wilcoxon, or other?

I'm newer to statistics and unsure how to analyze my data for a cohort study (n=73) where KAP assessments were administered to the same pregnant women before and after an educational intervention for ...
ram_i_rez's user avatar
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1 answer
147 views

Do I always have to consider all possible pairs in post-hoc pairwise comparison?

I performed an ANOVA on some test results of N groups (N = 7), which yielded a significant difference of the group means, followed by a wilcoxon signed-rank test to determine which groups are ...
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Study results showed that the posttest scores got lower than the pretest scores, yet wilcoxon results show that there is significant difference

We had a study on the effectiveness of a learning intervention. We collected pre and post test scores and the results showed us that the students' scores got lower in posttest than the pretest. But ...
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Wilcoxon sign rank test in R does not match with GraphPad Prism

I am comparing several combinations of two columns of non-normally distributed paired data: I used R with the following syntax: wilcox.test(x, y, paired=T) I tried to replicate this test in GraphPad ...
Karen's user avatar
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1 vote
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Is the Wilcoxon Signed Rank Test appropriate when the Brier score is the accuracy metric?

When comparing model performance, is it valid to use the Wilcoxon signed rank test for matched pairs, when the accuracy metric is the Brier score? (Here, the Brier score is used in calculating the OOB ...
Kyle's user avatar
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2 votes
1 answer
146 views

Wilcoxon Rank Test Pre/Post By gender

I am trying to compare the paired pre to post-responses in a student survey to see if gender plays a role. I was told to do a wilcoxon signed ranked test, and I can get the mean and p-value by each ...
Cam's user avatar
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1 answer
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How to run Wilcoxon signed-rank test for pairwise comparison of two factors with three variables each?

I performed a study where I took 9 measurements from each participant for 2 factors (time/ location) and 3 variables each. These created the following combinations: T1L1, T1L2, T1L3, T2L1, T2L2, T2L3, ...
tarun14110's user avatar
1 vote
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17 views

How to analyse ordinal data for five food samples

I've conducted a questionnaire asking participants to rate biscuit samples based on factors such as taste and look. The ratings ranged from strongly like to strongly dislike. What is the best method ...
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1 vote
1 answer
411 views

Paired sign and Wilcoxon tests with weighting

In R, I am using the survey package (inverse probability weighting) to conduct these tests on paired data: Weighted Wilcoxon Signed Rank test Weighted Sign test However, I am struggling in doing ...
Matteo's user avatar
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2 votes
1 answer
956 views

Statistical test to compare models results for concordance index

I'm working on a model for survival prediction and using the concordance index to evaluate the results (https://medium.com/analytics-vidhya/concordance-index-72298c11eac7) . I want to show that my ...
coffecake8284's user avatar
3 votes
1 answer
53 views

Test on significant difference

I need to test if there is a significant difference in leakage between prototypes. I've tried kruskal wallis and post hoc wilcoxon pairwise and Dunn-Bonferroni test, and the post hoc test always say ...
rklk sek's user avatar
3 votes
1 answer
203 views

Why is the pseudomedian better than the median in a Wilcoxon test?

The wilcox.test function in R calculates the pseudomedian and a confidence interval when conf.int=TRUE. In this question, ...
kidokin's user avatar
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1 answer
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One Sample Wilcoxon effect size

I am struggling with effect size calculations for the Wilcoxon test for one sample in R. My data: item1 <- c(1,5,3,4,4,2,3,2,1,4,5,4,3,1) ...
JPMD's user avatar
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1 answer
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Comparing standardised values of microbial colony perimeters

I’m having a statistical problem (a rather major one) and I was wondering if you could help. I’m researching microbial chemotaxis and analysing colony perimeters by scanning their fluorescence. ...
Cameron William Michael Murphy's user avatar
1 vote
0 answers
64 views

I'm having trouble choosing between Wilcoxon matched pairs test and McNemar test for a data set

I have a data set on a large group of long-term stroke survivors. I need to determine whether there is a difference in ability (on a scale of 1-10) between their left and right arms. The ordinal data ...
Harry_Fallows's user avatar
2 votes
1 answer
415 views

Wilcoxon signed-rank test - the "distribution of differences is symmetric" assumption

How do you define "symmetric" here? In a paired test scenario, if one treatment consistently produces better outcome than the other treatment, I'd imagine the differences to be clustered on ...
mp6's user avatar
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3 votes
1 answer
2k views

Post-hoc tests after Friedman test

In Statistical Comparisons of Classifiers over Multiple Data Sets (p. 12) Janez Demsar suggests to use the Bonferroni-Dunn test as a post-hoc test after the null hypothesis of an initial Friedman test ...
user378615's user avatar
2 votes
2 answers
45 views

Why is p value different in same hypothesis? [closed]

wilcox.test(weight ~ group, data = my_data, paired = TRUE) wilcox.test(weight , group, data = my_data, paired = TRUE) can anyone specify the difference to me ...
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