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

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16 views

Non parametric test [duplicate]

guys. I wanted to assess whether there is a significant difference between the means of three independent groups or not, but I cannnot use t test for them because the sample sizes are vastly different....
5
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3answers
276 views

Non-parametric alternative to simple t-test

I have five numeric variables of two populations (each of them with 60 individuals) and for each of those five variables I want to know if there is difference in the means. I was trying to use a ...
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0answers
17 views

Nonparametrics testing

i have some datasets which contains well name, mud type, and their caliper diameter. Lets say i have two types of mud. How to do some sort of statistical test that will give me some hypothesis that ...
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0answers
9 views

Intuition: What is the difference between linear factor models and regular linear regression?

So, I have a very vexing theoretical question that I hope some experienced econometricians can help me with. Being in finance, I have recently been exposed to linear factor models, which are models ...
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0answers
21 views

Weibull Kernel Evaluation [on hold]

I am trying to evaluate the work of Salha et al. (2014) entitled: "Hazard Rate Function Estimation Using Weibull Kernel" (http://www.m-hikari.com/pms/pms-2014/pms-1-4-2014/ahmedPMS1-4-2014.pdf). They ...
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0answers
33 views

Data Simulation weighted average [closed]

is it possible to simulate data, that follow: $Y_i = \sum_{j \neq i} w(i,j)\cdot Y_j +\epsilon_j $ So that $Y_i$ is a weighted average of all other $Y$'s? I'm thinking about this for a few days and ...
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1answer
31 views

Can I assess the relationship between a normally and non-normally distributed variable?

My study is related to the visual attractiveness of route-plans in a logistics context. In practice, route-plans are rejected based on the fact that they "do not look nice". I have conducted an ...
1
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0answers
30 views

Smooth regression algorithms that produce zero training error

I am looking to fit three regression functions $f_1, f_2, f_3:\mathbb{R}^2 \to \mathbb{R}$. For example, let's say $X_1$ is time, $X_2$ is geographic latitude, $f_1$ is the temperature, $f_2$ is the ...
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0answers
4 views

What test for 3-level * non-normality * non equality of variance (like Brunner-Munzel test for 2-level factor)

I have no data now though, I'm learning nonparametric statistics now. As I learned so far, nonparametric test for three-level design is Kruskal-Wallis test. But Kruskal-Wallis test needs the equality ...
1
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0answers
22 views

A' (A prime) for extreme Hit rates and False Alarms

I am trying to compute the non parametric measure of sensitivity A' according to the following formula reported by Stanislav & Todorov (1999): $$ A'= .5+sign(H-F)*((H-F)^2+abs(H-F))/(4*max(H,F)-4*...
-1
votes
0answers
25 views

Statistical power for nonparametric-based effect sizes

Does anyone know how to calculate power in GPower for effect size from r=z/sqrt of N (recommended for nonparametric tests by (Pallant, 2007 p. 223, and Tomczak 2014)? I used output from Wilcoxon ...
2
votes
1answer
58 views

UMVUE of distribution function $F$ when $X_i\sim F$ are i.i.d random variables

Let $(X_1,X_2,\cdots,X_n)$ be a random sample drawn from a population with distribution function $F$. Is the empirical distribution function $F_n$ the UMVUE of $F$? ( $F$ itself is the parameter of ...
2
votes
1answer
61 views

Is parametric Bayesian inference a special case of nonparametric Bayesian inference?

I'm thinking about univariate density estimation. Original Question In parametric inference, you assume the data are generated from a density that can be summarized by finitely-many parameters. You ...
0
votes
1answer
32 views

Assumptions of the Friedman Rank Test

Let $X_i:= (X_{i,1}, ..., X_{i,k}) $ for $i =1...n$ be $\mathbb{R}^k$-valued random Variables with $k\geq2$. I wonder what the exact assumptions are to apply the Friedman test to Realisations of ...
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0answers
14 views

Group comparision in repeated measures data with missing values?

I have data from blood samples collected from 20 patients before, during (at 30 min, 1 h, 2 h, 3 h, 4 h) and after a medical treatment (using the slightly different treatment protocols A and B). The ...
0
votes
1answer
25 views

What is the asymptotic distribution of the integrated MSE of the histogram for a discrete random variable?

Let $\{X_i\}_{i=1}^n$ be i.i.d. discrete random variables. Let $f_n(x) = \frac{1}{n}\sum_{i=1}^n \mathbb{1}(X_i=x)$. I am interested in the asymptotic distribution of $$\sum_x (f_n(x)-f(x))^2$$ I've ...
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0answers
11 views

In nonparametric methods, why do we assume the symmetric distribution of random variables?

I am studying statistics by myself with the book "An introduction to mathematical statistics". There are tests like sign test, signed rank Wilcoxon, etc. The book says the test statistics for those ...
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0answers
22 views

Comparing means of two groups with limited information

For my thesis I'm comparing the scores of my subjects (n=12) on a language-test with the controlgroup (n=40) of that test. For all my subjects I collected the number of correct items on 15 subtests (...
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1answer
46 views

Approximate a CDF

Suppose we have $n$ equations with an integral of the form $\int_0^{x_i} F(z)dz = c_i,\ i=1,\ldots,n$ where $F(y)=\mathbb{P}(X \le y)$ is an unknown cumulative distribution function of a non-negative ...
-1
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0answers
20 views

Comparison of non-parametric tests

What is the difference between Dunn's test of multiple comparisons, the Mann-Whitney U test, the Wilcoxon rank sum test, and chisq.post.hoc from the R package ...
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0answers
32 views

Dunn's test of multiple comparisons

From the documentation page for the R function dunnTest from the package FSA: Performs Dunn's (1964) test of multiple ...
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1answer
54 views

Fligner-Killeen test of homogeneity of variances interpretation

I have two samples that I want to verify that variances are equals in order to apply Wilcoxon rank sum test that assume that the variance are equals. Here a boxplot As you can see the variance ...
1
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2answers
29 views

2-ways anova for non-normal data

Our group took samples of contamination in sediments from around 20 non-related rivers, during 4 months. I want to know if contaminant (micrograms per liter) is related to river and/or time, thus my ...
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votes
1answer
24 views

mixing non-parametric correlation and parametric regression

I'm running both correlational and regression analyses on a variable that is not normally distributed: For correlations, I decided to use Spearman's rank correlation (which is non-parametric) due to ...
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0answers
24 views

Multiple regression to maximize Kendall's tau

I've seen methods for maximizing Kendall's tau using regression with a single independent variable, e.g. Sen's 1968 article. I'm interested in fitting coefficients in a multiple linear regression ...
1
vote
1answer
23 views

How can I run multiple tests in a valid and random fashion?

I hope this is the correct place to ask this question. I'm currently doing research where I'm comparing two groups on their EEG frequency spectra. I wasn't too sure how to approach this. Data: I ...
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0answers
23 views

Non-parametric analysis for between-subjects

I performed 3 experiments, each experiment tested a different system, and each experiment involved a distinct group of subjects. In total there where 25 participants (7 for the first system, 7 for the ...
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0answers
15 views

Suitable non-parametric test for comparing mean between two group [duplicate]

I have a data of dependent variable(risky driving behaviour) and 3 categorical variables. In 2 categorical variable( gender and car ownership) have 2 group and 1 categorical variable (driving ...
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0answers
8 views

the informal definition of the almost complete convergence

I'm searching for the informal definition of the almost complete convergence (P. L. Hsu and H. Robbins (1947), Dugué (1955)), which means a definition without any mathematics formula. Thank you for ...
0
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0answers
15 views

Kernel regression: Bandwidth selection on subsample

I have two columns of data which I sort by size (ascending) of the second column. I now want to execute a kernel regression on the first column (Nadaraya-Watson estimator) and I am interested in only ...
0
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0answers
15 views

Comparing effect of two variables

I have two IV’s (A) and (B) and a DV (X). The hypothesis is: (A) has a higher propensity to result in (X) than (B). X is Dichotomous. A and B are single 5-point Likert-scale questions. I’m ...
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0answers
46 views

Confidence intervals for collision probabilities

I have some random variable $X$ taking values in $\mathbb{N}$. $X$ has finite support (and so bounded mean, variance, etc) but of unknown size. Beyond that I know very little about its distribution. ...
1
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1answer
15 views

What does “number of ties of extent m” mean?

I'm trying to figure out how variance of Kendall's tau statistic is determined in the presence of ties. From Yue et al. 2002: The variance of $S$ is given by: $E(S) = \frac{n(n-1)(2n+5)-\sum_{m=1}^{...
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0answers
9 views

Can you use bray-curtis distances to evaluate standardized abundances in an NMDS?

So I'm trying to run an NMDS (using the vegan package in R) for a species X site matrix. Unfortunately the abundances of species are not inherently equal (If you can use that word) meaning that not ...
1
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0answers
15 views

Effect sizes for nonparametric 2x2 ANOVA (pre-post experimental design)

During the writing of my thesis, I stumbled upon the following problem: My data is not normally distributed (as expected) and the sample size is small (N=26, evenly spread over a control and an ...
1
vote
1answer
25 views

Two-Way Non-Parametric Test for Non-normal Data?

I have an unbalanced design with two factors, gender and site. I'm trying to test for differences in a size variable. Levene's test reveals that the data has equal variances. However, log transformed ...
1
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0answers
18 views

Non parametric tests for relation/association between variable

What could be an appropriate test for checking whether there exist any relationship between Net Promoter Score ( Categorical in nature with 0 meaning detractor, 1 meaning Neutral, 2 meaning Promter ) ...
4
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1answer
45 views

The Wilcoxon test for ordinal data

I would like to know if it is OK to use the Wilcoxon matched-pairs signed rank test to find significant differences between two sets of ordinal data, pre and post intervention (number of subjects is ...
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0answers
11 views

Two Variables: CPTED Audit Rating and Crime Count-Which test to use?

My project is focused on Crime Prevention Through Environmental Design, AKA CPTED. CPTED is a theory that certain characteristics of the built environment, such as level of maintenance, level of ...
1
vote
1answer
26 views

Statistical test for differences between proportions, with many zeroes

I have collected data in the form of percentages, ie. what % of the population has Trait A? I measured the frequency three times for each population, giving three replicates. My ultimate goal is to ...
2
votes
2answers
45 views

which non parametric test to use?

I'll start with saying I am not an expert in stats and had some basic knowledge of Anova but was now told to use the nonparametric test in my project and I'm lost. My design: I have two groups, low ...
0
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0answers
26 views

Coefficient of variation for nonparametric data [duplicate]

Is it appropriate to use the coefficient of variation (CV) for non-parametric data? I'm not sure whether it is appropriate since you use the mean of the data to calculate it together with the SD. ...
2
votes
0answers
22 views

Correcting Spearman's rank correlation for measurement error and range restriction

Many articles describe how to correct the Pearson correlation for both measurement error and range restriction.1,2,3 For some work I am conducting, I would like to estimate the Spearman rank ...
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0answers
6 views

Is it possible to compare species compositions using some kind of analysis: anosim, adonis or PERMANOVA but using presence/absence of data?

Is it possible to compare species compositions between three groupss using some kind of analysis: anosim, adonis or PERMANOVA but using presence/absence data?
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1answer
11 views

non parametric test to detect price discrimination

Let us say that I have these columns for a product: Day Price Channel of sale (e.g. web or snail mail) Number of sales Looking at the distribution, they can be bi modal as products can be on sale/...
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0answers
12 views

Are non-parametric test effective when my pairwise-evaluation data is multiplied through different distributions?

So, I've designed an experiment where I compare pairs of texts that have been clustered. I want to test a few different aspects of the data so I've created 8 different distributions and selected 100 ...
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2answers
65 views

What does the size of the Wilcoxon rank sum test 'W statistic' indicate?

I wish to see whether the average meal masses of two species are significantly different, and I have sample sizes of >800 for both. My Wilcoxon rank sum test returns a W = 330520 value - how should I ...
2
votes
1answer
39 views

Piecewise exponential model - how to fit

I'm trying to go through the following paper: https://projecteuclid.org/download/pdf_1/euclid.aos/1176345693 it covers the piece wise exponential model for modelling hazard rates in a non-parametric ...
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0answers
49 views

Select from Sign Test and Signed Rank Test based on assumption or power

I'm testing the difference of a paired dataset. I need to select between sign test and Wilcoxon signed rank test. I have read ...
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0answers
19 views

Is it ok to re categorize my variables this way?

I have a 2^3 factorial design, where the dependent variable is binary, and the three independents are binary and I care about interactions. I've seen that you can use logistic regression, but I feel ...