All Questions
Tagged with nonparametric r
235
questions
0
votes
0
answers
80
views
Non-Parametric Two Way Within-Subjects ANOVA
I have a dataset with 4 individuals that are measured twice in each of the 5 groups (so in total 40 observations).
Subject
ID
Group
Value
1
1
A
45
1
2
A
62
1
1
B
70
1
2
B
37
...
...
...
...
4
2
...
- 1
2
votes
4
answers
467
views
I want to show by simulation that the Wilcoxon test is more robust than the Student test for non-normally distributed data
I want to test by simulation that the Wilcoxon test is more robust than the Student test for non-normally distributed data.
For example, I'm testing the ...
- 919
0
votes
0
answers
45
views
ACME Significant in Mediation analysis, but not Proportion Mediated and Fitting terminated with step failure warning
I am running a series of mediation analyses in R using the mediation package and the following code:
...
- 65
3
votes
1
answer
117
views
Nonparametric way to perform ANOVA of linear mixed model for small sample and power calculation
I have a small data where there are 3 groups (A,B,C) and 5 participants from each group. All of those participants are measured 6 times on each of 7 different exams, so each participant get 6*7=42 ...
- 77
0
votes
0
answers
39
views
Data is not normal, want to test for interaction too Any non-parametric test? [duplicate]
I have a sample size of $310$ individuals that comprises samples collected along the elevation gradient and at different times. I want to see how the variables differ along the elevation, and with ...
- 73
1
vote
1
answer
38
views
Estimate multivariate distribution with several variables on real data (continuous and categoricals) and sample from it
I have a complex dataset, collected through a survey, with both continuous (such as Age, Body mass index, etc..) and categorical variables (i.e. Gender, Education, etc..). I want to estimate their ...
- 11
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 ...
- 13
0
votes
0
answers
64
views
Multivariate analysis for non-normal variables
Edit: I am trying to produce a model in R in order to analyze the relationship between several variables. I am looking at the relationship between behaviour and dispersal of a population. Each ...
1
vote
2
answers
2k
views
Non-parametric test for comparing means of 2 or more dependent variables in R?
I have a matched paired dataset (student survey before a topic was taught and student survey after the same topic was taught) where I compare the means of their answers (answers are given in Likert ...
denise
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 ...
- 63
6
votes
1
answer
589
views
Alternative to Friedman Test in R
I am trying to run a Friedman Test in R with a repeated measure, however, my data do not qualify as an unreplicated complete block design. I am wondering what ...
- 75
1
vote
1
answer
262
views
Non parametric 2 way anova
In my dataset, there are two distinct species, each with three unique treatments. My objective is to investigate whether there are any significant differences among the various species and treatments. ...
- 11
1
vote
1
answer
160
views
How to use the argument stype in boot-package in R? [closed]
The stype argument in boot of R can take 3 values: "i" which is the default, "w" or "f".
What is ...
- 151
0
votes
0
answers
29
views
Calculating p value using Bootstrap in R for nonparametric test
Im trying to approximate the p. Value using bootstrap in R by boot function
But in the result is repeated i.e the values of t0 ….tn are the same so the p value is zero !!!!! I don’t understand why ...
0
votes
1
answer
485
views
which non parametric test is best for ordinal data?
I want to to do the test where i have to check if first column which is income, and 1 shows < 500, 2 = 1000, 3 = 2000 income values from the data, and which the other column which is a dependent ...
- 31
1
vote
2
answers
71
views
which non parametric test to use? friedman or Kruskal?
I am conducting a study on textrual complexity. We fed people food (3 types) over 3 sessions and asked questions about hunger levels. 20 participants were tested during 60 trials in total. Of the 14 ...
- 11
1
vote
0
answers
109
views
Trouble interpreting Friedman Test for 3-way repeated measures ANOVA
I would like to use a Friedman Test as a non-parametric alternative to a 3-way ANOVA in RStudio. I would like to measure how 'cl_conc' (Response Variable) is affected by 'soil_type' (Fixed Effect #1 - ...
- 35
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:
...
- 165
1
vote
0
answers
15
views
Looking for associations between nominal and non-parametric continuous data
I'm a first-year BSc Biology student working on my end-of-module stats project, so that's the expected level of my work.
I need to find associations between hindlimb length and frog locomotor modes (e....
- 11
0
votes
1
answer
347
views
Linear mixed effect model, repeated measures or non-parametric test?
I have this study design: two groups (A & B) measured in 3-time points (pre, follow-up & post). I thought that a linear mixed model effect was the preferred option because I do have missing ...
0
votes
0
answers
50
views
A huge non-normal, heteroscedastic dataset with multiple groups. How to test?
I have a dataset with approximately 38,000 measurements of sizes of cysts from 64 kidneys from 5 different groups.
We have a hypothesis that the distribution of the sizes (small to huge) is different ...
- 101
2
votes
0
answers
69
views
When is the central limit theorem not applied?
I am trying to compare two matched samples. In total I have a sample of 34 people. Each patient receives two treatments, a C1 treatment and a C2 treatment. So each patient will be compared to himself ...
- 919
7
votes
1
answer
3k
views
bootstrapping a linear mixed model with R's lmeresampler or lme4 or a robust regression?
considering that I have a very small sample and that my residuals are non-normally distributed, I've decided to perform a lmer() with bootstrapping. This is my very ...
- 781
2
votes
2
answers
294
views
What should be normally distributed for a two-way repeated measures ANOVA? R
When running a two-way repeated measures ANOVA, should:
A) the independent varibles be normally distributed?
B) should the scores between the variables be normally distributed?
Overall: should the ...
- 781
1
vote
0
answers
140
views
how well would a robust mixed model fit these data? R (rlmer)
I want to investigate Y ~ X1 * X2 + (1|ID on this dataset (there's a plot of these data in that post too, it's the same dataframe)
Y is a continuos outcome ...
- 781
1
vote
4
answers
131
views
Business use cases for Wilcoxon signed-rank test
The Wilcoxon signed-rank test is generally used for non-parametric data (i.e. not normally distributed). When the sample gets large, the data will be approximately normally distributed. Therefore ...
- 11
2
votes
1
answer
395
views
Experience with Kruskal-Wallis versus Zero-Inflated Kruskal-Wallis as nonparametric alternative to one-way ANOVA
I have a data set of 1 categorical predictor (4 levels) and one non-negative continuous response variable (listed as "aphidleaf in histogram). The response variable is not count data and the ...
- 101
2
votes
0
answers
194
views
How to conduct a boostrapped or a permutation wilcoxon test (in R)
I have a total of 18 mice, 9 from Healthy group and 9 from Sick group. Since I have a very poor sample size I would like to use boostrapping or permutation test.
Is there a way to conduct a ...
- 579
2
votes
1
answer
541
views
NA p-value in R cor.test
$R$ gives "NA" for the p-value when I try to run Kendall's test with an "exact p-value" flag set on a larger data set (n=170 seems to be the cutoff). Is this just a computation ...
- 159
1
vote
1
answer
2k
views
How to handle ties in pairwise wilcoxon rank-sum test?
I am willing run the wilcoxon rank sum test for different combination of variables, and using the base R code, I get a lot of warnings. The reason is that there are so many (about 30% of the whole ...
- 143
2
votes
0
answers
171
views
Cross-validation on the HP filter for penalty selection
I'm looking for a bit more clarification on the selection of the $\lambda$ value for the Hodrick-Prescott Filter, aka HP filter. Which stems from a time-series in the form of
$$y_t=g_t+\epsilon_t$$
...
- 569
1
vote
1
answer
400
views
How to extract the penalty term from the GAMM function in R and what is used to estimate the penalty terms
I'm working on some log GDP data and I am testing out a Generalized Additive Mixed Model for it with a penalized cubic regression spline. I am using the GAMM function from the mgcv package in R and I ...
- 569
3
votes
2
answers
687
views
Inference of nonparametric tests as linear models
I found some statements throughout the web that suggest that most common statistical tests can be performed as general(ized) linear models (cf. here). For a Wilcoxon test the author of the referenced ...
- 159
0
votes
0
answers
275
views
How can I perform a Tetrachoric and Polychoric Correlation on variables that aren't normally distributed?
From everything I have read, both tetrachoric and polychoric correlations assume normal distributions. However, the data I want to conduct these correlations with is not normally distributed. Does ...
- 101
2
votes
0
answers
51
views
Nonparametric ANOVA for simulated data
I have some simulated data and I want to test whether "group" has an effect. The data are from a Weibull distribution. because the data are simulated, I can determine sample size, however ...
- 469
0
votes
0
answers
21
views
Which test when I have paired observations in more than two treatments?
I have doubts on which test I should use when I have measurements on the same individuals under more than 2 different conditions.
I have a sample of rats, on which was measured the effect of different ...
- 139
0
votes
1
answer
367
views
Fitting an functional autoregressive model in R with mgcv
I'm working with the 'mgcv' package in R and I just want to know if I am going about the right way of fitting a functional autoregressive (FAR) model. The FAR model is represented as
$$Y=f_1(x.1)x.1+...
- 569
0
votes
0
answers
211
views
How does imperfect stripping affect Aligned Rank Transform ANOVA?
I have tried using ART ANOVA (ARTool) recently for two-way analyses, but I keep getting the warning that ART may not be appropriate because "F values of ANOVAs on aligned responses not of ...
- 1
0
votes
0
answers
65
views
Wilcoxon Rank Sum Test appropriate?
I'm using Wilcoxon Rank Sum Test on my data and I'm wondering if there is a better alternative to use and eventually what post-hoc I could do on my data.
Context: The objective is to find the ...
- 113
2
votes
2
answers
530
views
Mean difference analysis for a paired data with zero inflation. Can Wilcoxon test work?
I have a set of data that represent the sum of white matter streamlines termination in 64 regions of interest in the brain surface collected from 40 subjects.
Below is an example of a paired data of ...
0
votes
1
answer
95
views
How to detect differences between two repeated measures for not-normally distributed variables, adjusting for a continuous covariate?
I'll explain briefly the experimental set-up.
One gruop of subject measured in two conditions:
A: with treatment (Instrumented gait analysis with foot orthosis)
B: without treatment (Barefoot ...
1
vote
1
answer
230
views
Why does my omnibus test do not agree with post hoc test?
So I am running a simple Dunn's Test on my data. After running the Kruskal-Wallis H Test, it returned a result
...
3
votes
2
answers
975
views
Does aligned rank transform ANOVA require normally distributed data?
Initially, I wanted to do a two-factorial (4x3) repeated measures ANOVA in order to analyse my data.
To be more precise, I do have two factors with factor1 having 4 levels (A, B, C, D), factor2 having ...
- 31
0
votes
1
answer
339
views
Trying to use R nparLD to test for between group variation in repeated measures
I am trying to determine if my subjects differ for a specific variable by sex. I have tried using nparLD but it only tests if my individuals differ between trials, not if there is variation between ...
1
vote
0
answers
189
views
quantile regression result different from Mann-Whitney U test
The results of the quantile regression and Mann-Whitney U test are very different. My sample size is 39. The quantile regression returns p-value of 0.83, while Mann-Whitney U test gives 0.33.
Why are ...
- 1,499
1
vote
1
answer
2k
views
P-value correction for multiple comparisons using Mann-Whitney test (using R)
I have one question regarding the adjusted p-value for multiple comparison using Mann-Whitney test.
The data structure that I am dealing with is something like this:
Two groups to compare: Group 1 vs ...
- 335
1
vote
0
answers
134
views
Tests for positively skewed data with large enough samples?
I'm new to statistic tests so I need a little bit of help with them. Most of my data has distribution similar to the histogram below.
As it can be seen from the histogram, the data is positively ...
1
vote
0
answers
148
views
Effect size using nparLD library RStudio
I would like to calculate the size of the effects using RStudio for writing an article.
I have longitudinal data taken in 4 time points: baseline, day 20, day 50 and recovery (one month after) in a ...
- 21
3
votes
1
answer
214
views
Random forest with nonnegative dependent variable
I have a modeling framework with an outcome that must necessarily be positive. In the training data, the outcome ranges from close to zero to much higher (approximately 0.05 to 100). Is there a way to ...
- 725
1
vote
0
answers
96
views
Time Varying Coefficient Model with Uniform Kernel and Spline Estimator
I'm working on the BMACS data set data(BMACS) from library(npmlda).
I'm looking at the the time-varying coefficient model of post-CD4 versus smoking $X_1$, pre-HIV CD4 percent $X_2$ (centered) and age ...
- 25