0
votes
0answers
8 views

In practice, how is the penalisation matrix for splines, created by smoothCon (package mgcv), specified?

Evaluating a smooth object with smoothCon provides, besides several other things, the ordinary "untouched" spline bases ...
0
votes
0answers
12 views

Problems with calculation of numerical identification w.r.t. ANOVA smooth for large scale matrices

Suppose we have two (centered) Spline-matrices $\boldsymbol{B_1}$, $\boldsymbol{B_1}$. Then $\boldsymbol{X_1} = [\boldsymbol{B_1},\boldsymbol{B_2}]$ contrains lower order smooths and ...
1
vote
0answers
33 views

Repeated measure two-way ANOVA (non-parametric)

Non-parametric ANOVA – a hot topic that is unanswered. There are many questions on this topic online. However, they all seem to end in a debate and no definite answer or clear explanation (that I ...
4
votes
0answers
49 views

How exactly is the sum (or mean) centering constraint for splines (also w.r.t. gam from mgcv) done?

The data-generating-process is: $y = \text{sin}\Big(x+I(d=0)\Big) + \text{sin}\Big(x+4*I(d=1)\Big) + I(d=0)z^2 + 3I(d=1)z^2 + \mathbb{N}\left(0,1\right)$ Let $x,z$ be a sequence from $-4$ to $4$ of ...
1
vote
0answers
45 views

How does the cubic spline basis exactly look like

By the definition (1) $S(x)=\begin{cases} S_0 = a_0x^3 + b_0x^2 + c_0x + d_0, & \text{if }t_0\le x\le t_1\\ .....\\ S_{k} = a_kx^3 + b_kx^2 + c_kx + d_k, & \text{if }t_{k-1}\le x\le ...
0
votes
0answers
18 views

How to analyse individual consistency from three non-normally distributed variables?

I would like to know if individuals were consistent across three different days. I measured the latency of individuals for a maximum of ten minutes. Many individuals had a latency of 0 and some ...
1
vote
0answers
20 views

Kruskal-Wallis test for factorial design [duplicate]

Is it possible to use the Kruskal-Wallis test for two factors and their interaction (i.e., two way ANOVA: Y~a*b)? And which post-hoc test is possible to use after ...
0
votes
0answers
20 views

What is the test used in R in sm.regression to compare reference model with kernel regression?

I am doing bivariate kernel regression using the sm.regression function: http://cran.r-project.org/web/packages/sm/sm.pdf There is an option to compare the nonparametric estimate with linear model. ...
0
votes
0answers
66 views

Is there any model that includes random effects with non-parametric data distribution?

I have a non-parametric (by which I mean non-normal) data distribution. I tried several transformations, but none were helpful. Now, I want to find a model where I can include random effects with the ...
3
votes
1answer
360 views

How to convert from Mann-Whitney U to Z (or other effect size)?

I'm looking at multiple studies. I do not have the original data. One study I'm looking at provides means, standard deviations, and Mann-Whitney $U$ values (with $p$). (How) can I convert from ...
0
votes
0answers
31 views

Bandwidth selection in multivariate semi parametric estimation in R (np package)

I am estimating a semi-parametric and a full non parametric model, by using the np package in R. I have more than 400 observations for T big years, moreover several ...
4
votes
1answer
108 views

Entropy estimation for a symbol sequence

I am looking for an R-implementation of the Lempel-Ziv data compression algorithm, to estimate the source entropy of a time-series consisting of a sequence of symbols. Rather than simply measuring ...
3
votes
1answer
177 views

Hypothesis testing - Wilcoxon test, bootstrapping, or something else?

A colleague has developed a treatment for to "prevent falls" in cognitively impaired, psychiatric patients. Since this would be very useful treatment in this population, we especially do not want to ...
5
votes
1answer
132 views

Friedman test vs Wilcoxon test for binary IV

I'm trying to assess performance of a supervised machine learning classification algorithm. The observations fall into nominal classes (2 for the time being, however I'd like to generalize this to ...
2
votes
2answers
50 views

Influence of two factors on non-normal outcome. Which test?

I measured two variables (outcomes) $Y_a$ and $Y_b$ for several subjects. $Y_a$ and $Y_b$ are continuous variables defined on $[0,100]$ and have a bimodal distribution. I tried using a transformation ...
7
votes
1answer
3k views

What is the non-parametric equivalent of a two-way ANOVA that can include interactions?

Hi I am trying to find the non-parametric equivalent of a two-way ANOVA (3x4 design) which is capable of including interactions. From my reading in Zar 1984 "Biostatistical analysis" this is possible ...
5
votes
1answer
112 views

State of the art: Non parametric density estimation with a boundary and data clumped near zero

I have some data which I wish to estimate the marginal distribution of. I have no real idea what parametric distribution would be suitable, so was planning on fitting a non-parametric (probably ...
0
votes
0answers
52 views

Testing significances in Likert type items

I have a questionnaire of 18 questions with Likert-type answers, going from 1-5. One of them was administered to parents, one to their children. I need to test 2 thing: a) within each group, are the ...
0
votes
0answers
85 views

Exact p-value for any nonparametric test

After having found the R-package coin, I have a question. For example, to get an exact p-value, I could use the function ...
0
votes
0answers
31 views

Multidimensional nonparametric test of variance

Let's say I have two or more sample populations of $n$-dimensional continuous-valued vectors. Is there a nonparametric way to test whether or not these samples have the same variance? e.g. like a ...
1
vote
0answers
165 views

Test if multidimensional distributions are the same

Lets say I have two or more sample populations of n-dimensional continuous-valued vectors. Is there a nonparametric way to test if these samples are from the same distribution? If so, is there a ...
1
vote
0answers
677 views

Power analysis for Kruskal-Wallis or Mann-Whitney U test using R?

Is it possible to perform a power analysis for the Kruskal-Wallis and Mann-Whitney U test? If yes, are there any R packages/functions that perform it?
0
votes
0answers
34 views

Non-random distribution of SNPs (single-nucleotide polymorphisms)

I have a bunch of groups of DNA sequences in which I have observed changes in different regions (block D and H) vs. the rest of the molecule. The data is available as a table like the one below. The ...
1
vote
2answers
109 views

Nonparametric test

To get the power of the t-test I use this R code: pwr.t.test(n=25,d=0.35,sig.level=0.05,type="one.sample",alternative="greater") and for the test of the Pearson ...
0
votes
1answer
378 views

Best way to test runs

I have the following sample: ...
1
vote
2answers
159 views

Robust ANCOVA literature

I am looking for some source of information, some articles about Robust ANCOVA. Can you suggest me something? And do you know any source that directly gives information about how to perform various ...
5
votes
1answer
2k views
1
vote
0answers
192 views

Help with Theil-Sen regression function (written in R)

I have written a function (in R-language) to perform a Theil-Sen regression with large sample approximation (please see below). It seems to work well for the one-sided case as illustrated in ...
1
vote
0answers
206 views

Repeated Measures in R, SAS or SPSS: Whale Body Temperature Data

I have a question regarding a repeated measures experiment. I have 5 whales (randomly selected) that I recorded body temperature on. Data was collected via satellite, programmed to transmit records at ...
5
votes
3answers
348 views

How to test my data against an specific normal distribution?

I need to test my data to see if it follows a normal distribution with specific mean and std like N~(mu, std) I know that this can be done by Kolmogorov-Smirnov test which has a function in both ...
3
votes
0answers
503 views

How to interpret results from non-parametric ANCOVA?

I 'm new to the CV and not very good at statistic:) I would much appreciate some help on a non parametric ANCOVA in R sm package. I do a pre post analysis on a set of pre/post variables of two groups ...
1
vote
1answer
153 views

Randomization Tests

The following data are mandible lengths (mm) of 10 male and 10 female golden jackals Canis aureus in the collection at the British Natural History Museum. The two samples are independent. ...
1
vote
0answers
298 views

Non-Parametric Regression with Ordinal Independent Variables

I'm trying to find a model to predict a test score (0 to 100) from many independent ordinal variables (all are on a 1 to 10 scale). Since there are SO many ordinal variables, using binary dummy ...
1
vote
0answers
40 views

How do I extract difficulty and discrimination from a non-parametric IRT model

I've been using the KernSmoothIRT module in R to do non-parametric analysis of some items. I'm trying to find a way to quantify the difficulty and discrimination ...
1
vote
0answers
238 views

Intuition behind tensor product interactions in GAMs (MGCV package in R)

Generalized additive models are those where $$ y = \alpha + f_1(x_1) + f_2(x_2) + e_i$$ for example. the functions are smooth, and to be estimated. Usually by penalized splines. MGCV is a package ...
1
vote
0answers
112 views

Which 'delta' to use from those returned by 'orddom' package in R with argument 'paired = TRUE'?

I have used the orddom package in R with the argument paired = TRUE to calculate the Cliff’s delta for paired groups, and a ...
7
votes
2answers
1k views

Permutation test in R

I have the following data for 10 subjects based on before and after measurements: ...
2
votes
1answer
823 views

Comparison between bootstrap percentiles confidence interval and BCa confidence interval?

I have generated a nonparametric percentiles bootstrap confidence interval ($32.27143, 51.08571$), and a BCA confidence interval ($33.26, 53.49$) with an initial sample size of $n=7$. Evidently, the ...
3
votes
0answers
742 views

In R, why are results different for 1-tailed wilcoxsign_test, wilcox_test, and wilcox.exact with paired data?

I am trying to determine why I am getting different results with these different Wilcoxson test implementations in R version 2.15.2. I have paired data with some ties. I have read the response for ...
4
votes
1answer
2k views

Nonparametric equivalent of ANCOVA for continuous dependent variables

I have an independent categorical variable ($X$ with two categories, $x_{1}$ and $x_{2}$) and two continuous dependent variables ($y$ and $z$). Using a Mann Whitney test, I know that $y$ is ...
3
votes
1answer
1k views

Two-sample one-sided Kolmogorov-Smirnov test vs one-sided Wilcoxon-Mann-Whitney test

I've read in the library manual for test ks.test that The possible values "two.sided", "less" and "greater" of alternative specify the null hypothesis that the ...
1
vote
0answers
60 views

Linearity and ordinal variables in nonparametric setting

I am using the np package in R with the npregiv command. The program is in beta, and I cannot call ordered(var) on one of my instruments (a bug in the program I am ...
7
votes
1answer
2k views

Is there an alternative to the Kolmogorov-Smirnov test for tied data with correction?

I've got a bunch of data from two samples (control and treated), each containing several thousand values which are to undergo significance testing in R. Theoretically, the values should be continuous, ...
12
votes
1answer
2k views

Is there an optimal bandwidth for a kernel density estimator of derivatives?

I need to estimate the density function based on a set of observations using the kernel density estimator. Based on the same set of observations, I also need to estimate the first and second ...
1
vote
0answers
1k views

Non-parametric alternative to linear regressions in R

I want to run series of simple lm in R, with a continuous/categorical outcome and binary group membership (patients - controls) and categorical predictors. However the categorical predictor is ...
1
vote
1answer
393 views

Post-hoc analysis on Friedman's test

I am using a Friedman's test with post-hoc analysis. I am using the function friedman.test.with.post.hoc available for R software. Lets say we have 6 wines and we ...
8
votes
2answers
729 views

Wilcoxon-Mann-Whitney critical values in R

I have noticed that when I try to find the critical values for the Mann-Whitney U using R, the values are always 1+critical value. For example, for $\alpha=.05, n = 10, m = 5$, the (two-tailed) ...
5
votes
0answers
448 views

Kaplan-Meier multiple group comparisons

Lets say I have the following data frame ...
1
vote
2answers
221 views

Assuming my three data series are each $\chi^2(1)$ distributed, are they different from eachother?

I systematically chose rare words from three groups of texts (#1, #2 and #3) (the rare words within each group are different, but some rare words may appear in more than one group). Then, for each ...
8
votes
2answers
10k views

How to run two-way ANOVA on data with neither normality nor equality of variance in R?

I am working on my master thesis at the moment and planned on running the statistics with SigmaPlot. However, after spending some time with my data I came to the conclusion that SigmaPlot might not be ...