All Questions
Tagged with nonparametric r
235
questions
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