All Questions
Tagged with nonparametric multiple-comparisons
55
questions
0
votes
0
answers
12
views
When is Tukey post hoc test result identical to Games Howell post hoc test for Welch ANOVA?
In what situations is the Tukey post hoc test identical to the Games Howell post hoc test? I have an ANOVA analysis where HOV is violated and I have a statistically significant Welch ANOVA result. I ...
- 321
0
votes
0
answers
29
views
Why does the Dunn's test in online calculator rejects the null hypothesis while my manual computations cannot reject it?
In my own manual calculations of the Dunn's Test in google sheet, using the formula from a YouTube video, I managed to calculate the same Test Statistic as the online calculator.
However, using the ...
1
vote
2
answers
341
views
SIgnificant ANOVA but not significant post hoc ... what can I do?
I am analyzing some IHC data on the density of cells in two brain regions(factor 1) in two closely related species(factor 2). My data is composed of an n of 6 for each species and is not normally ...
0
votes
0
answers
72
views
Dunn test in R: comparison between levels of a single factor in a 2-factor experiment
For a 2-factor experiment, the TukeyHSD function in R (after a significant ANOVA) can calculate P values for the differences between levels of a single factor (basically, comparisons between the ...
- 53
3
votes
1
answer
53
views
Bonferroni correction gives weird results in R
I have this dataset:
Treatment
data
T1
0
T1
0
T1
0
T10
0
T10
0
T10
0
T11
0.2
T11
0.2
T11
0.2
T12
0
T12
0
T12
0
T2
0.7
T2
0.6
T2
0.6
T3
0.8
T3
0.7
T3
0.8
T4
0.3
T4
0.3
T4
0.4
T5
...
- 53
3
votes
1
answer
207
views
Kruskal-Wallis returns only one significant group (out of 4 groups), when significant group is removed and test redone, another group is significant?
I am comparing 4 groups of samples using SPSS. The groups are 4 bathymetry groups (>0m, >-1m, >-2m, >-3m). Within each group are a number of samples n. Each sample has a recorded seagrass ...
- 31
2
votes
2
answers
262
views
Need for bonferroni correction
I need help understanding if I need to / how to apply a bonferroni correction!
I have one continuous variable and three unrelated groups that have completed scores on this variable (Groups: A,B,C). I ...
- 31
1
vote
1
answer
1k
views
How to do pairwise comparisons for Kruskal Wallis test?
If the null hypothesis in the Kruskal Wallis test is rejected, How can we perform pairwise comparisons? Can we apply Dunnett's Test for that?
- 11
1
vote
2
answers
82
views
Are t-tests good choices here?
I would like to test if two groups of participants (dark-eyed and light-eyed individuals) respond to a drug differently over time. The hypothesis is that the drug reaches its peak effects sooner but ...
- 13
1
vote
1
answer
43
views
Which pair of two distributions are more similar?
Suppose I have two pairs of distributions: distributions A and B in Pair 1, distribution C and D in Pair 2. There are non-parametric tests to determine if there is evidence to say that the ...
- 125
0
votes
0
answers
229
views
On assumptions and calculation of O'Brien's "Global Statistical Test" for Multiple Endpoints Analysis
As I understand, O'Brien's Global Statistical Test (GST) (https://pubmed.ncbi.nlm.nih.gov/6534410/) for Multiple Endpoints Analysis is a method for mapping a multivariate problem on a univariate scale....
- 127
3
votes
1
answer
198
views
Multiplicity correction after performing non-parametric tests
This is a theoretical question.
I am wondering if multiplicity correction is applicable in the case of non-parametric tests.
I have performed some Mann-Whitney U rank test on two independent samples ...
- 120
1
vote
1
answer
2k
views
How do I interpret the p-value in a Dunn-test?
I conducted a Kruskal Wallis test for my sample sizes, and this is what I got:
Kruskal-Wallis chi-squared = 12.138, df = 4, p-value = 0.01635
The p-value is below 0.05, so I know there is a ...
- 15
4
votes
2
answers
2k
views
Which pairwise comparison tests are best to use after the Kruskal-Wallis test (Dunn, Conover-Iman or Steel-Dwass-Critchlow-Fligner test)?
I have 3 sampling sites where I took 3 water samples in each site. I chose to do the Kruskal-Wallis test to find out if there is a significant difference in total nitrogen between the sites. I did not ...
2
votes
0
answers
460
views
Multiple comparisons version of Kolmogorov-Smirnov test
Suppose $\mathbf{y}_{i} $ and $ \mathbf{x}_{i}\,$ are length-$m$ vectors and $D_{i}$ is some arbitrary distribution $(i=1,...,N)$. I would like to conduct the following hypothesis test:
$ H_{0}: \...
- 388