All Questions
Tagged with nonparametric t-test
96
questions
2
votes
1
answer
4k
views
Paired t-test for skewed data
I have a cohort of subjects (n=262) with a single-time intervention. Subjects have been asked to answer on a questionnaire before and after the intervention. The questionnaire comprises five items ...
- 679
7
votes
2
answers
12k
views
Non-Parametric altervative to one sample t-test
I have a the following hypothesis: $H_0: \mu=4$, $H_1: \mu\neq 4$, which I wanted to test using a one sample t-test.
However, my data is not normally distributed and a transformation was not found. ...
- 486
2
votes
1
answer
705
views
Comparisons on nonparametic, unequal variance data
I am trying to compare financial investment of 2 groups, however, my data is not normally distributed AND has unequal variance between the two groups. I thought of using the Mann-Whitney on SPSS but I ...
- 23
2
votes
1
answer
100
views
dependent T-test or Wilcoxons signed rank for small sample size?
I am doing an EEG study with a small sample size (N=13) and I have many variables that I need to compare (for example, onset of readiness potential, maximal point of RP, time or awareness, etc), so i ...
- 21
1
vote
3
answers
2k
views
Using t-test/ANOVA on bounded data
Can a t-test/ANOVA approach to hypothesis testing be carried out when data has well-defined upper and lower limits and is not continuous?
Let's assume a situation where data are generated by some ...
- 11
3
votes
1
answer
6k
views
similarities between t-test ,welch test and mann whitney test
I am newbie to statistics field.
I find it is quite hard to understand this few tests even though they are common tools for testing hypothesis.
As i am referring this paper actually "should we always ...
- 33
6
votes
3
answers
5k
views
Comparison of medians in samples with unequal variance, size and shape
What am I trying to do and how does my data look?
I am trying to perform some comparisons of medians of groups of data that, most often than not, are not-normally distributed. In some cases I am ...
- 421
6
votes
2
answers
370
views
What is an example of data where the permutation test succeeds but a normal t-test fails?
In literature, I normally see authors use a two sample permutation test on normal data to show that it works as well as the two sample t-test. However, the real power for permutation tests should be ...
- 2,107
1
vote
1
answer
58
views
non parametric or parametric test for means of groups?
I have a series of experiments that are done in a series of blocks(groups). When comparing the means of group 1 and group 2 that arent statistically significant p=0.84. However looking at the group 1 ...
- 13
0
votes
0
answers
838
views
Comparing means between two groups if dependent variable is a percentage
I have data on recovery rates from several hospitals across the country. The recovery rates are in percentages.
I want to compare the mean recovery rate between two groups of hospitals, one that uses ...
- 1
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 ...
- 23.8k
2
votes
1
answer
2k
views
How to compare two variables with different distributions?
I want to compare 2 independent variables, but the problem is that the first variable is normally distributed, while the second variable is not. What is the appropriate test in this case? Can I use an ...
- 21
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 ...
- 582
1
vote
0
answers
312
views
Non parametric anova or two non parametric ttest?
I have a statistical question about a project I recently got.
We performed a flow cytometry assay on 3 different groups: controls (n=5), patients before treatment (n=5) and paired patients after ...
- 501
7
votes
4
answers
9k
views
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 ...
- 551