Questions tagged [nonparametric]
Use this tag to ask about the nature of nonparametric or parametric methods, or the difference between the two. Nonparametric methods generally rely on few assumptions about the underlying distributions, whereas parametric methods make assumptions that allow data to be described by a small number of parameters.
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Relation between the sample size with the powers of Kolmogorov Smirnov, Cramer Von Mises and Anderson Darling?
I want to know the mathematical relation between the sample size with the powers of 1. Kolmogorov Smirnov, 2. Cramer Von Mises, and 3. Anderson Darling.
I have seen many posts and other websites ...
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Estimation of Propensity Score using Random Forests
Suppose that one has a binary treatment $Z$, and assume that $Z=1|X=x \sim Bern\left(e(x)\right)$.
Furthermore, suppose I want to estimate the propensity score by a random forest. Are there ...
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Kruskal-Wallis as a non-parametric alternative to 2-way ANOVA?
I'm a master student currently working with taxonomy and cultivation of wild edible mushrooms. In my experiment, I'm evaluating the effect of 4 distinct solid culture media and 4 temperatures on the ...
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How to deal with negative values after subtracting the background?
I am working with Luminex data and have a question regarding the treatment of negative values after subtracting the background average. Specifically, I would like to know if these negative values need ...
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Statistical test for differences where output is -1, 0, 1?
He's the situation, say we have n data points. There are two treatments A and B. If treatment A was better than treatment B we give a score of 1, in the opposite case we give a -1, and if there is ...
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How to compare more than two groups of continuous, not-normally distributed values?
I'm currently analyzing the age variable in a dataset of all italian phyisicians (~470,000 obs) and I'm trying to check if age is significantly different between three groups defined by another ...
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Calculation of a nonparametric equal-tailed (central) tolerance interval for an unknown continuous distribution
Assume we have a sample of size $n$ from an unspecified continuous distribution $F(\cdot)$. We wish to construct a tolerance interval to contain $(100\,\beta)\%$ of the population with a pre-specified ...
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Comparing non-normal data between three groups
I am analyzing a dataset, where I have 3 categories (independent variable), and one continuous value (dependent variable). I am studying if the continuous value is significantly different between the ...
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How to measure reproducibility for repeated measures
I have run an experiment where in a series of trials, each of 10 animals was presented with each of 6 stimuli, and each stimulus was offered once to the left and once to the right nostril. Overall, ...
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Distribution and variable analysis
I am doing a statistical test (program used is SPSS). On the basis of distribution and sample size, I have to chose the correct variable analysis. I also have to justify every decision. I have two ...
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Non-parametric test with two independent variables
My dependent variable is a raw score at some test that has a likert scale (ordinal data). My two independent variables are sex (male or female) and amyloid status (AB+ or AB-). I want to test the main ...
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Seeking suggestions for a non-parametric version of two-way ANOVA/multi-variable MANOVA with repeated measures
I've been reading around this and keep coming up short so I'm hopeful there's an easy test for this.
I am measuring the differences (on a Likert scale) between matched (paired) pre- and post-lesson ...
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Fuzzy RDD and IV
I understand the close analogy between a fuzzy RDD and Instrumental Variables estimation. This is clearest in the Wald Estimator. Here is the Fuzzy RDD equation:
And here is the (manual) estimation ...
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Is there a package/function in R, Matlab or Python to perform smooth non-parametric fitting of empirical CDF data? [closed]
I have numerical process that generates percentiles values of a certain random variable $X$, meaning that I have $x_i$ values and their corresponding probability values $\hat{F}(x_i)$.
I want to fit a ...
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Multiple Linear regression unmet assumptions, what can I do?
I need your help with some work I am doing.
Some context first:
I am writing a dissertation for my master. The topic is about perceived trust in Smart Home technology. I launched a survey with a ...
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Gronwall's inequality
I am reading the article.
I am getting stuck with the first proof proposition 4 on page 32.
To be more specific, they understood the reason why they obtained $F(x) \le \frac{2K}{1-\frac{2R\epsilon}{\...
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Kolmogorov Smirnov Test Consistency
I was reading that the Kolmogorov Smirnov 2 sample test is consistent, that is Probability of rejection under $H_1$ is 1 for sample size going to infinity.
Say we have 2 random variables X and Y. K-S ...
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Is there a statistical test for five groups with averages ONLY?
The data I collected was measuring plant shoot masses and these were extremely small, so I could only find the total mass of the shoots from 30 plants. Hence, I only have the mean and none of the ...
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Can I use log-log OLS with no constant to measrue the relationship between two variables in a non-normal distribution?
I am trying to measure the relationship between the price of a futures-contract and the current price of the underlying asset on the day of purchasing said futures-contract. For this I have a dataset ...
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How to run Wilcoxon signed-rank test for pairwise comparison of two factors with three variables each?
I performed a study where I took 9 measurements from each participant for 2 factors (time/ location) and 3 variables each. These created the following combinations:
T1L1, T1L2, T1L3, T2L1, T2L2, T2L3, ...
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What test can I use to compare for discrete counts from two independent samples
I need some assistance. Its driving me crazy. So I have two independent populations, I sample them at different points to obtain ordinal count data. However, at each point the sample sizes used to ...
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Expected value (and variance) of a Dirichlet Process
Suppose I have a measure $G$ that follows a Dirichlet Process,
$$G \sim DP(H_0,\alpha)$$
where $H_0$ is some base measure. Is there a closed form solution for the expected value of $G$?
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Is density estimation the same as parameter estimation?
I was studying parameter estimation from Sheldon Ross' probability and statistics book. Here the task of parameter estimation is described as follows:
Is this task the same of density estimation in ...
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Convert Cohen's d to nonparametric effect size and use as equivalence bounds
In a within-subjects design (n = 30), I had planned to run equivalence tests with the equivalence bounds set at the effect size of Cohen's d 0.35. This is partly based on previous research and partly ...
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Kruskal-Wallis returns only one significant group (out of 4 groups), when significant group is removed and test redone, another group is significant?
I am comparing 4 groups of samples using SPSS. The groups are 4 bathymetry groups (>0m, >-1m, >-2m, >-3m). Within each group are a number of samples n. Each sample has a recorded seagrass ...
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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 ...
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How to Replicate result that probabilities in included table are different 7 times?
Question: In the table at the bottom of this question, the total number of times that $\hat{P}(x;z) > \hat{P}_y(x;z) $ and $\hat{P}(y;z)>\hat{P}_x(y;z)$ is 7.
Can someone please replicate this ...
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What is non-parametric regression?
The screenshot below is from a paper that I am reading and the author says it is a non-parametric regression. The explanation below just seems like a normal OLS with some covariate, fixed effects.. ...
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Is there an optimality result for the two-sample Wilcoxon-Mann-Whitney test?
Is there any mathematical result that states that the Wilcoxon-Mann-Whitney (WMW) test is optimal in some sense, for a specific testing problem that is a subproblem of the general problem the WMW test ...
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Equivalence test for nonparametric one-way ANOVA
I have hypothesised equivalence among 3 repeated measures. The data are such that a nonparametric approach would be needed.
What I have considered, but not necessarily know how to implement correctly:
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