Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [parametric]

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Why are parametric tests more powerful than non-parametric tests?

I'd like to understand why parametric tests are more powerful than their non-parametric alternatives. Is the word choice of "power" the same as statistical power? As I understand it, power just relates to the likelihood of getting a p-value that…
Nate
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Why are parametric models usually robust to mild misspecification?

Statisticians often use parametric families of models, for example normal distributions with unknown mean and variance. However, nothing in real life is perfectly normally distributed (or distributed according to any other simple parametric family),…
alligator
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Are there any parametric machine learnig models that can represent non-linear behaviour between a predictor and a targe variable?

Some basic models, like multiple linear regression (MLR), are parametric but usually limited to linear interactions between X and y. Other models can represent non-linear interactions between X and y, but to my understanding, most of these are…
Henrique
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Example of a parametric family of distributions that always has dependence on among its variables

Inspired by this question, I would like an example of a parametric family of distributions such that there is dependence for all choices of parameters. The family could be infinite or finite, but I would like the support to be infinite. Can such an…
DifferentialPleiometry
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Which test should I use to compare a normal distribution sample with skewed distribution sample?

I have two groups : Infection group (n=26) and healthy control group (n=127). The aim is to see if there is a difference in the mean of T cells absolute count* values between the two groups. Ho= the infection group’s T cells absolute count mean is…
Mounmoun
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Survey sampling: How many participants per group (current, former, and potential users) should we recruit?

We are designing research in which we will explore the perception of users (C current, F former, and P potential) on a product. We apply the same questionnaire for each group adapting (verb tenses) some questions depending on user group (C, F, and…
Juan Quintero
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When is a hypothesis test appropriate?

For example, when would a hypothesis test bed used?
Ljones
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Data didn't pass normality testing for K-W and S-W but the skew and kurtosis were within range...advice please?

I am conducting a study on the relationship between rural/urban living, intentions and barriers to help seeking in adult males. I was planning to conduct a correlation and then pending that result, a MANOVA (no correlation) or a MANCOVA (should…
Rachel
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Generating samples from custom distribution using parametric bootstraping in R

I am given a dataset generated from the following distribution: $f(y|\alpha,\beta)=\alpha*\beta^{\alpha}*y^{-(\alpha+1)}$ for $y\geq \beta$ The assumption is that $\beta=2$. The dataset has 8 data which gives a mean of $2.765$. Now,I need to use…
Jeffrey
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Fit parametric distribution with data coming from multiple parameter values

I have $N$ samples and I would like to fit them to a parametric distribution, for example beta-binomial. \begin{equation*} X_i \sim \textit{Beta-Binom}(\alpha, \beta) \end{equation*} If all samples were from a single distribution with a single set…
Eaman
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Power calculation for two populations of equal variance

If I had a scientific assay which when run on a control population produces readouts which are normally distributed about the mean. A treatment which changes this mean does not change the variance of the population, just the mean. That is to say any…
j1ling67n
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Can I use parametric statistic tests if data are normally distributed in each group, but not overall?

I have a control group defined by a certain variable (say values 0-5) and an sick group (values between say 5-20). Within each group the data are normally distributed, but (off course) not when looking at the the whole cohort. Am I allowed to use…
Sara
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What repeated measures statistical tests should I use with uneven sample size and parametrical/nonparametrical distribution?

I'm looking for a way to measure significance + variance homogeneity/heterogenity First of all I tested my data for normality and it's not always parametrical, so I think that I should use different tests for parametrical/nonparametrical data (fig 1…
denver1000
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Should I use a parametric test or non-parametric test?

I'm analysing a set of data on the fluorescence intensity of a particular receptor. All the data are in the form of a fraction as they are being compared to a control. ie. fraction = intensity of test sample/intensity of control. Are the set of…
Fayth144
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Differences between parametric and non-parametric models

Aside from the number of parameters and their behavior with the sample size, are there any other significant differences between parametric and non-parametric models? Is there any situation where we would prefer to use one of these models over the…
MLNewbie
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