# Questions tagged [small-sample]

Refers to statistical complications or problems due to having few data. If your question is about a small sample relative to the number of variables, please use the [underdetermined] tag instead.

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### How to choose between t-test or non-parametric test e.g. Wilcoxon in small samples

Certain hypotheses can be tested using Student's t-test (maybe using Welch's correction for unequal variances in the two-sample case), or by a non-parametric test like the Wilcoxon paired signed rank ...
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### Can bootstrap be seen as a "cure" for the small sample size?

This question has been triggered by something I read in this graduate-level statistics textbook and also (independently) heard during this presentation at a statistical seminar. In both cases, the ...
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### Warning in R - Chi-squared approximation may be incorrect

I have data showing fire fighter entrance exam results. I am testing the hypothesis that exam results and ethnicity are not mutually independent. To test this, I ran a Pearson chi-square test in R. ...
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### Best method for short time-series

I have a question related to modeling short time-series. It is not a question if to model them, but how. What method would you recommend for modeling (very) short time-series (say of length $T \leq 20$...
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### What can we say about population mean from a sample size of 1?

I am wondering what we can say, if anything, about the population mean, $\mu$ when all I have is one measurement, $y_1$ (sample size of 1). Obviously, we'd love to have more measurements, but we can'...
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### Can you be 93.75% confident from a random sample of only five from a population of 10 000?

I recently read this passage from a website and I just can't work out the math. Overall, it says you can be 93.75% confident of having the true median parameter within an interval, obtained from a ...
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### How to perform Student's t-test having only sample size, sample average and population average are known?

Student's $t$-test requires the sample standard deviation $s$. However, how do I compute for $s$ when only the sample size and sample average are known? For example, if sample size is $49$ and sample ...
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### How to cope with exploratory data analysis and data dredging in small-sample studies?

Exploratory data analysis (EDA) often leads to explore other "tracks" that do not necessarily belong to the initial set of hypotheses. I face such a situation in the case of studies with a limited ...
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### Using bootstrap under H0 to perform a test for the difference of two means: replacement within the groups or within the pooled sample

Suppose that I have a data with two independent groups: ...
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### Appropriate normality tests for small samples

So far, I've been using the Shapiro-Wilk statistic in order to test normality assumptions in small samples. Could you please recommend another technique?
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### Mother milk of 6 Corona-positive (COVID-19) women does not contain the virus - can we make a confidence statement about this?

I am asking this question because I believe it would be great if the statistics community could make a contribution to solving this serious puzzle until more evidence is available. The UK Royal ...
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### Can a small sample size cause type 1 error?

I've learnt that small sample size may lead to insufficient power and type 2 error. However, I have the feeling that small samples just may be generally unreliable and may lead to any kind of result ...
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### Topic stability in topic models

I am working on a project where I want to extract some information about the content of a series of open-ended essays. In this particular project, 148 people wrote essays about a hypothetical student ...
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### Does machine learning really need data-efficient algorithms?

Deep learning methods are often said to be very data-inefficient, requiring 100-1000 examples per class, where a human needs 1-2 to reach comparable classification accuracy. However, modern datasets ...
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### Is Random Forest suitable for very small data sets?

I have data set comprising 24 rows of monthly data. The features are GDP, airport arrivals, month, and a few others. The dependent variable is number of visitors to a popular tourism destination. ...
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### Mean(scores) vs Score(concatenation) in cross validation

TLDR: My dataset is pretty small (120) samples. While doing 10-fold cross validation, should I: Collect the outputs from each test fold, concatenate them into a vector, and then compute the error on ...
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### Machine learning models for regression on small data sets

What are the "best" models to be used for simple regression of 1 numerical variable using only a small data set of e.g. 250 samples and up to 10 features? I understand that the data set is super ...
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### Is significance of the p-value reliable with extremely small sample sizes? [duplicate]

As I'm completely new to statistics and clinical trials, I would ask you for help and clarification. Let's assume we have 2 really small samples (each of n = 2, or so) derived from two normally ...
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### Multiple regression with small data sets

I have a dataset of project case studies for a new type of research method for Government agencies to support decision making activities. My task is to develop an estimation method based on past ...
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### Elastic net arbitrary alpha selection

I'm trying to solve a prediction problem given the following constraints: I need an interpretable model to be used for experimental validation I need a model that performs feature selection to reduce ...
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