Procedures that rely on relatively few assumptions about underlying probability distributions.

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3
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1answer
18 views

Multiple comparisons in a non-parametric test

I am working with a data set that is non-parametric and has 12 treatments. I performed the Kruskal-Wallis test and got a significant $p$-value, and now I would like to conduct a multiple comparisons ...
0
votes
2answers
28 views

Which test do i choose to conduct on my Likert scale data?

I have been doing plenty of research into which test I should use on my Likert scale data and i am becoming more confused as there are so many people saying different things. I am currently doing my ...
1
vote
1answer
22 views

Approaches for extracting single-year age estimates from age-buckets

I'm trying to estimate a binary function of $Y$~$Bernouli(p_{i})$ where $p_{i}=f(age)$ where f is an unknown continuous function. There are obviously a lot of methods to try to reconstruct f (splines, ...
1
vote
0answers
37 views

How does the cubic spline basis exactly look like

By the definition I'll have (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 ...
0
votes
0answers
15 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 ...
0
votes
0answers
6 views

Reliability Measure for Unequal Subjects between Raters?

I am comparing two medical imaging analysis techniques, and I would like to assess the inter- and intra-rater reliability for using each method. I am planning the study design, and would like help ...
0
votes
1answer
18 views

Is system identification and learning examples of parametric or nonparametric methods?

Difference between parametric and nonparametric statistical tests and What is the difference between distribution free statistics/methods and non-parametric statistics? is a good read for beginners. ...
1
vote
0answers
8 views

Identify significant deviations (gaps) of points in a 2-D distribution

Consider an $X_i$, $Y_i$ distribution of points in a 2D plane. How can one assess if a given region in this 2D plane has a significant lack of points when comparing with the rest through a ...
0
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1answer
29 views

Statistics Test for bivariate frequency table

First time user here! I have some troubles in finding some statistic method that would fit my purpose for testing bivariate frequency table. Below is a sample frequency table I have created with ...
4
votes
0answers
39 views

Nonparametric test for largely skewed count data

My research design looks as follows: an experimental game with 4 participants (human subjects), repeated for 20 rounds. During each round, participants are allowed to form bilateral coalitions which ...
6
votes
6answers
340 views

Dealing with non-normal distribution in “big” datasets, when do we throw out the CLT?

Apologies from the go as this question comes from an absolute newbie and will definitely not satisfy a lot of the detail required. Hence, your guidance in providing you the right information to allow ...
4
votes
1answer
50 views

Nonparametric ANOVA with interaction?

Is there any nonparametric version of ANOVA able to deal with multiple factors AND evaluate their interaction(s)? If the interactions are really impossible to evaluate, is there any generalization of ...
0
votes
1answer
31 views

Difference between skewed continuous variable and/ or ordinal variable by their binary group allocation

I need to select the most appropriate hypothesis test to answer: "whether there is any difference between variable 1 (ordinal) and/or variable 2 (continuous) by group (binary)". This is a randomised ...
1
vote
0answers
19 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 ...
2
votes
1answer
50 views

Absolute variable as dependent variable

I have the following model: $$ |X| = B_0 +B_1 \cdot y + B_2 \cdot z , $$ where $z$ and $y$ are normally distributed random variables, and $B_1$ and $B_2$ denote the coefficients. My dependent ...
0
votes
0answers
18 views

Is there an alternative to paired t-test two multilevel ordinal variables? (similar to McNemar test)

Suppose I have two variables that measure some form of severity of illness on identical ordinal scale; one measured before treatment and the other measured after the treatment. I want to test if ...
1
vote
1answer
35 views

What is the difference between a parametric test and non-parametric tests? [duplicate]

Please explain the difference between a parametric and a non-parametric test. Do all data mining techniques come under the non-parametric category?
0
votes
1answer
31 views

Bootstrap hypothesis testing with small sample sizes

I have 2 campaigns (a control and a test campaign), the data are like this: ...
1
vote
0answers
43 views

Testing specific categories after Fisher's exact test in 2 x k tables

I have two variables, one with 2 categories and one with 6 categories. To test, whether there is any relation between these variables, I performed Fisher's exact test, which gave a significant result. ...
4
votes
1answer
98 views

Computing inverse probability weights — conditional (multivariate) density estimation?

The general version: I need to estimate $f(A | X)$ where $A$ and $X$ are continuous and multivariate. I'd rather do it nonparametrically because I don't have a good functional form in mind and ...
0
votes
0answers
24 views

Best non-parametric test for continuous dependent variable and binary independent variables

I am struggling with the choice of which test would be appropriate for my data. My sample size is very small (n=16), thus I have chosen to perform a non-parametric test in order to prove my ...
2
votes
2answers
68 views

are “non-parametric” methods well-defined?

I have trouble understanding the delineation of "non-parametric" methods. It seems to me most non-parametric methods are parametric, just on a different space than the "standard ones". Graph-based ...
0
votes
0answers
13 views

Statistical test decision tree / reference card

I'm in need a reference card to help in deciding which statistical test to use depending on study design, variance, class size, groups, etc. Anything like this available?
0
votes
1answer
33 views

Ignore assumptions and still go ahead with a parametric test?

I have data which is not normally distrubuted (histogram doesnt show a bellshape data and normal plot shows a bit of a zig zag data going through line of best fit) but standard deviations are of ...
2
votes
1answer
46 views

Hypothesis testing for multiple choice quiz

I am trying to determine whether students perform better than chance on a quiz with $q$ multiple choice questions. Each question as 4 possible responses; one is correct and 3 are wrong. A correct ...
0
votes
0answers
8 views

Generalizing van Elteren to more than two treatments

I know about the following tests: Mantel-Haenszel for categorial stratified data Kruskal-Wallis for nonparametric ANOVA for more than two treatments Friedman for a repeated measures version of ...
4
votes
2answers
75 views

Non parametric measure of strength of association between a discrete and a continuous random variable

I'm throwing here the problem as I received it. I have two random variables. One of which is continuous (Y) and the other one which is discrete ordinal (X). I put below the plot I received together ...
2
votes
1answer
24 views

How to deal with non-normal heterocedastic data from a factorial experiment?

I ran an experiment with two factors each with two levels, 5 replicates each combination and one response variable. My data are non-normal and heterocedastic. Transformations didn't help. I ran a ...
0
votes
0answers
15 views

Splines, latent variables and model identification

For $J$ units of observations my basic model contains latent variables $\theta_j, j = 1, ..., J$ identified by the marginal assumption $\theta \sim N(0,1)$. The latent variables are connected to a ...
0
votes
0answers
14 views

Nonparametric test when variances are unequal [duplicate]

I have to compare two groups with data that are not normally distributed and have unequal variances. Which nonparametric test is to be used when variances are different?
0
votes
1answer
42 views

When is the IID Assumption too strict for the bootstrap?

The Bootstrap (Efron 1979) assumes that the data are IID. Obviously, if we have time series data then we probably cannot make that assumption unless we have a special case that we a time series of ...
0
votes
0answers
26 views

How to compare two independent KS tests?

I have two vectors of observed data obs1 and obs2, and two vectors of expected data exp1 and ...
1
vote
0answers
37 views

Can I use wilcoxon signed rank test for time series data

I have a question about wilcoxon signed rank test. I have 2 different speed profiles (speed starts from time 0 to 100 sec) of the same participant that was given 2 different treatment. I would like to ...
2
votes
1answer
23 views

Prediction from gam model at X = 0 not equal to intercept

I'm having a problem with GAM. Specifically when I try to make a prediction at a new data value at the origin, my prediction is not equal to the intercept. Can someone help me understand why this is ...
3
votes
0answers
30 views

Interpret the pairwise comparison plot from SPSS

For my user study, I am trying to find out to what extent people prefer to move by foot. They had the option to rank their preference for 'walking', 'jogging' and 'running' for a several amount of ...
3
votes
0answers
24 views

Power in proteomics?

Grants often require power analysis to support a proposed population size. In proteomics (and most -omics), there are 100's to 1000's of features/variables measured across 10's of samples (maybe 100s, ...
0
votes
0answers
22 views

Can I use Pearson correlation for small dataset if I care about a difference?

I have small dataset that cannot be extended (rare disease) in which I have 30 instances characterized by 20 features each. The features are concentrations from spectrometry (scale var). As I care ...
0
votes
0answers
15 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
13 views

Is a rank means stat appropriate?

I have attached an image of a subset of data consisting of snow measurements (D1-D6) taken at unique locations (Site1-Site25) over the course of several years. Each measurement was taken at the same ...
3
votes
2answers
67 views

I don't understand what is going on with my t-test and Mann-Whitney results

I have 2 samples, A and B. I subjected both samples to extraction and got the amount of yield (the dependent variable). I just want to see if there is a significant difference between the yield for ...
4
votes
1answer
131 views

Is multicollinearity a concern in nonparametric statistics?

Should I be concerned about multicollinearity in nonparametric statistics?
1
vote
0answers
42 views

What are some examples of applied machine learning problems that requires using mixed models?

What are some examples of applied machine learning problems that requires using mixed models? I'm just introduced to the notion of mixed models. As I understand it, it is a combination of parametric ...
4
votes
1answer
129 views

A question on a non-parametric estimating equation

This is a question that arose from studying Hogg and Craig "Introduction to Mathematical Statistics",7th edition, pg 568. It is assumed that we have taken a random sample of $X_1,\ldots,X_{n1}$ and ...
1
vote
0answers
26 views

Comparing reaction tests

I have an experiment where every person needs to take reaction tests when he/she is sober, then when lightly and then heavily intoxicated. I need to perform a test that tells if the intoxication had ...
3
votes
1answer
94 views

Hypothesis testing for non-normal data

I'm measuring the error produced by operators executing planar cuts under different guiding systems. I define a target plane and then measure the euclidean distance from uniformly sampled points in ...
0
votes
0answers
21 views

Two Groups Time 1 and Time 2 Nonparametric

I want to look a the effect of an intervention on work satisfaction and motivation. The data not normally distributed. I have two groups, intervention and control, with 11 in each group. I measure ...
2
votes
2answers
61 views

What is more important in choosing parametric or nonparametric tests - skewness & kurtosis or normality test results?

There are often differences between results of Skewness & Kurtosis and normality tests, and I have always doubts if it is better to choose parametric or nonparametric tests (I use SPSS). Sometimes ...
2
votes
1answer
27 views

Gaussian Process and Expectation Propagation time complexity?

What's the time complexity of training a Gaussian process and its Expectation Propagation approximation? (Before studying them, I'd like to understand if they are even feasible for my application)
1
vote
0answers
22 views

Maximum likelihood estimation and density estimation

Let's consider a general signal processing estimation problem where the measurements are modeled as $${\bf x}[n]={\bf s(\theta)}+{\bf w}[n],$$ where ${\bf w}$ is a non-Gaussian r.v. (noise term) and ...
0
votes
1answer
39 views

Alternative to Chi-Square, etc for categorical variables

I am trying again to explain my problem, and I have more concrete results. I have tried every potentially relevant test I can find, and none seem to work quite right. The question is illustrated ...