All Questions
Tagged with nonparametric t-test
96
questions
4
votes
2
answers
2k
views
Student's t vs Mann-Whitney U
I want to see if there is any difference in the number of dangerous permissions requested by free vs paid apps in Android store. I have equal sample sizes of 1900. When I plot the data they are both ...
- 711
7
votes
4
answers
9k
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Should I use t-test on highly skewed and discrete data?
I have samples from a highly skewed dataset about users' participation (e.g.: number of posts), that have different sizes (but not less than 200) and I want to compare their mean. For that, I'm using ...
- 9,427
140
votes
8
answers
121k
views
How to choose between t-test or non-parametric test e.g. Wilcoxon in small samples
Certain hypotheses can be tested using Student's t-test (maybe using Welch's correction for unequal variances in the two-sample case), or by a non-parametric test like the Wilcoxon paired signed rank ...
- 9,427
8
votes
3
answers
46k
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What is a minimum sample size for a paired t-test and what is a non-parametric equivalent if data is non-normal?
I have 4 sample pairs, let's say (x1, y1),...,(x4, y4).
What is the minimum sample size for a paired t-test?
Which assumption should I check for paired t-test?
If my data is non-normal, what is an ...
- 286k
6
votes
1
answer
21k
views
Non-parametric version of paired t-test (Mann–Whitney U test)
I have data from 100 individuals doing a 2AFC under a control and a manipulated setting. I want to compare the means. I initially used a paired t-test. My supervisor noticed the distributions were not ...
3
votes
3
answers
1k
views
Papers About Permutation Version of Welch's t-test
Permutation tests seem to provide a promising alternative for the unpaired t-test, requiring fewer assumptions. However, the core assumption of the permutation test, exchangeability, implies ...
7
votes
1
answer
2k
views
Use of Wilcoxon test for non-normal data akin to Two One Sided T-test
I'm analysing paired data for equivalency and it's not normally distributed, i.e., the difference of the paired result is not normally distributed due to, amongst other things, outliers. If it were ...
1
vote
1
answer
57
views
Very small degrees of freedom when using yuen function in WRS2 package of R
I'm trying to run a number of independent samples t-tests. I'm using the yuen function in the WRS2 package because my data are non-normal and ordinal. My sample ...
- 5,213
3
votes
1
answer
695
views
I have applied many statistical tests to my data, but still cannot determine normality
I have run multiple tests to determine normality on my dataset, but I am unsure which one to adhere to, especially since my histograms, density plots, and QQ plots leave much to be desired in terms of ...
- 15.9k
3
votes
1
answer
131
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If I have a very small n for one group and a very large number of features, should I choose a parametric or a non-parametric test?
I have a dataset that contains human metabolite concetration in a fluid. One group has about 12 samples, while another only has 5. My question is if I can assume normality for this data and do ANOVA/t-...
1
vote
0
answers
44
views
Which Non-Parametric Test should I use?
I want to make sure I am choosing the right statistical test.
I am working with 7 semesters of exams scores for a particular course.
Each semester the course ran with many sections. However, the ...
- 58.6k
63
votes
7
answers
54k
views
Which permutation test implementation in R to use instead of t-tests (paired and non-paired)?
I have data from an experiment that I analyzed using t-tests. The dependent variable is interval scaled and the data are either unpaired (i.e., 2 groups) or paired (i.e., within-subjects).
E.g. (...
2
votes
2
answers
296
views
Justification for conducting independent samples t test on non normal data
I've conducted a study comparing two different teaching strategies in two different sections of the same class; I gave participants in both classes the same 5 tests and wanted to see if test grades in ...
- 15.9k
2
votes
1
answer
513
views
Wilcoxon signed-rank test with an additional covariate
Problem formulation
I have 5 strains on which I administered treatment and repeated the experiment two times independently. So my data looks something like this:
...
- 11.5k
5
votes
2
answers
1k
views
Comparing P value from t test vs. Mann-Whitney test
If you analyze the same data with a t test and the nonparametric Mann-Whitney test, which do you expect to have the lower P value?
- 278