How many participants do you actually need for your study?
This is one of the most important questions in statistics because your sample size determines both the reliability of your results and the overall costs.
❌ If your sample is too small, real effects may not be detected, even if they truly exist. This can lead to incorrect conclusions.
❌ If your sample is too large, you may spend more time, money, and effort than necessary.
Power analysis helps you find the right balance between reliable results and efficient use of resources.
The visualization below shows how the required sample size varies with the effect size. When the effect size is small, a large number of participants are needed to detect it reliably. As the effect size increases, the required sample size decreases. This highlights a fundamental principle of study design. Small effects require large samples, while large effects can be detected with fewer participants.
I recently released a new module in the Statistics Globe Hub that explains how to perform sample size calculation using power analysis. The module includes a video lecture, practical examples, and exercises to help you apply the method step by step in R.
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Join the Hub now to get immediate access to the Statistical Power module and all other modules released this month.
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statisticsglobe.com/hub
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