# Questions tagged [sample-size]

This tag is very ambiguous. Use it when the question is about sample size and NONE of the following are more appropriate: [small-sample], [large-data], [power-analysis], [power], [underdetermined] or [unbalanced-classes].

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### Sample size calculation with different standard deviations

when calculating the required sample size with a given power and p threshold, usually the calculator only requires two estimated population mean and standard deviation. is it always valid to assume ...
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### Optimal Allocation Proof [duplicate]

I'm trying to derive the optimal allocation formula for but I'm not sure where I'm supposed to start with the derivation. If anyone can help point me in the right direction, that would be greatly ...
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### Optimal Allocation Proof [closed]

I'm trying to derive the optimal allocation formula for but I'm not sure where I'm supposed to start with the derivation. If anyone can help point me in the right direction, that would be greatly ...
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### Simulate data for multilevel & multivariate logistic regression

I want to simulate data for a multilevel logistic regression with several independent variables. I tried doing this with the steps of >>Arnold, B. F., Hogan, D. R., Colford, J. M., & Hubbard,...
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### What is the formula to determine the sample size for machine learning models?

I know that as a general rule the sample size needed to build a model using n independent variables is 10xn, however, is there a more accurate formula to determine the sample size?
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### How to simulate standard deviation

I would like to simulate data based on real data captured. The real data captured is 15 observations. The simulation based on the existing data is 100 observations. I have a mean and standard ...
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### Determining sample size from a Bayesian problem

I was following up on this problem when it seemed to me that the correct answer was ambiguous. I will not re-state the problem since it can be found in the original link. I will use the same notation ...
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### Reagent batch change, sample size, results significancy

We are working on a biological protocol measuring a patient's feature using a blood sample. This protocol has proven to have some variability (CV <= 10%). During this process we sometime need to ...
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### How does a small sample size (underpowered study) affect the prevalence?

I am doing a meta-analysis where I calculate an overall prevalence value for multiple studies. I have submitted my manuscript to a journal. I used sample size as one of the risk of bias criteria, ...