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Manual Event (Session ID,DateTime,Event) = 2m6qc142fgh2si9ho3378idgjr 20220129162944 /communities/sample-size-calculation/

Sample size calculation

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casslau
30 October 2019
Sample size calculation

How to calculate sample size for purposive sampling (Non random sampling)? We have 25 factors identified for our evaluation. How to calculate exact sample size for non random sampling?

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Jason Jiang
20 February 2020

Confidence intervals and standard error rates have no meaning when the sampling (or at least the assignment to test groups) is not random regarding the factors that you want to test.

Reference: https://www.researchgate.net/post/Do_you_know_any_sample_size_calculation_for_nonprobability_purposive_sampling_technique

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Hobbs
11 February 2020

It is very useful information! thank you!

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Ng Yuen Hang
30 October 2019

There is no way to estimate sample size when the sample is from non-random sampling. One can only assume the use of random sampling to set the minimum. Typically for any evaluation, the assumption of random sampling suggests a size of 780 cases for an expected weak effect size, 123 for an expected medium effect size, and 46 cases for an expected strong effect size, to achieve 95% in confidence and 80% in statistical power. It thus depends on the weakest effect size expected.

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