All Questions
28
questions
1
vote
1
answer
582
views
Welch's t test vs Mann-Whitney for very unequal groups
I have two vastly unequal groups (n1=18 and n2=400), and want to test mean differences between the groups for some 700 parameters (more specifically, RNA expression levels for 700 genes).
While I ...
- 33
0
votes
0
answers
39
views
Appropriate test for two not-normally-distributed data samples
I have some data comparing training participants who experienced the same training course either face-to-face or virtually (via Zoom). I have two survey items I am comparing. Sample A is for virtual ...
2
votes
2
answers
337
views
Concept Clarification: Wilcoxon rank test vs two-samples T-test (UPDATE)
I am currently deciding whether to use the Wilcoxon rank test vs two-samples T-test to assess BMI between two unrelated groups. Using the following code to assess normality ...
- 361
0
votes
1
answer
345
views
Interpret Mann–Whitney U Test with highly skewed data
I have data for ~102,000 hands of bananas. The dataset has four data points:
Spiders present (True/False)
Count of rotten bananas in hand
Count of total bananas in hand
Percent of bananas that are ...
- 245
2
votes
2
answers
43
views
Is there a way to quantify how appropriate a t-test is for given data?
I'm doing some programming and analysis for a post-doc who used to do this workflow using Excel and StatPlus. Apparently StatPlus has some feature where you tell it to compare two samples, and it will ...
- 241
4
votes
1
answer
164
views
T-Test or U-Test
I have a number of items that are based on a Likert scale, with values ranging from 1 = not at all to 5 = very much so. I would like to compare answers to these questions between two groups. I would ...
- 125
1
vote
0
answers
670
views
Mann-Whitney U Test and Independent t-test give different results, which to use?
I have two population and I want to know if the means of the two populations are different. To the best of my knowledge, I should try an Independent t-test if the data is normality distributed and ...
- 65
5
votes
2
answers
178
views
Wilcoxon (WMWU) test sensitivity
Statistics courses often give the Wilcoxon-Mann-Whitney U test ("Wilcoxon" from now on) as an alternative to the two-sample t-test.
However, the test is not quite the test of medians that would be so ...
- 65k
2
votes
1
answer
2k
views
Which statistical analysis should I perform if the data sets are not normally distributed?
I am doing an experiment where there are two independent groups; one is the group of "infected" patients another is the group of "sepsis" patients. I am comparing "platelet monocyte aggregates(PMA)" ...
1
vote
1
answer
722
views
How to find the difference between two set of scores of a single participant?
What I am trying to do?
I have a data set which consists of only one undergraduate student's all courses scores. Let's assume, he has completed about 70 courses where 40 courses are related to ...
- 294
1
vote
1
answer
216
views
Variance in a T-test using means/medians
I have turning data for animals in different conditions with comparisons of before and after these conditions, we'll say condA condB.
Each animal has 3 repeats on both conditions, where before a ...
- 127
1
vote
2
answers
404
views
Appropriate statistical test for data which do not have normally distribution and do not have equal variance
My data has 150 samples and is not normally distributed, and it does not have equal variances either. I know t-test (e.g. this python method) can be used when data is normally distributed and it can ...
- 271
1
vote
0
answers
690
views
Bayesian Wilcoxon test
I have a pre-post dataset with 2 observations per subject (propotion data -bounded between 0 and 1-).
I have analyzed the data with a classical dependent t-test under the NHST paradigm. However, as ...
- 157
1
vote
2
answers
926
views
wilcoxon mann whitney or t-test?
I would like to compare the number of a particular type of disease that is prevalent in men vs women. The number of diseases is interval data (0,1,2,3,etc). Should I use the wilcoxon mann whitney or t-...
- 107
3
votes
1
answer
2k
views
Non-parametric equivalent of the 1-sample t-test (not paired)
I have a sample of outcomes of my algorithm and would like to test to some degree of confidence if it differs from zero.
I know I can use a 1-sample t-test (as in https://docs.scipy.org/doc/scipy/...
- 213