Tag Archives: sample size

Calculating sample size for a 2 independent sample t-test

Scientists often plan for studies by calculating how many subjects or units need to be tested in order to find an effect. That is, they plan for a study using statistical power according to principles of hypothesis testing. Sample size calculations are usually required in ethics applications and grant proposals to justify the study. We previously learned how to calculate

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Power failure in the neurosciences

There is evidence that many (and possibly most) of the conclusions drawn from biomedical research are probably false (Ioannidis, 2005). In a 2013 Nature Reviews Neuroscience paper entitled “Power failure: why small sample size undermines the reliability of neuroscience”, Button et al. explained how low statistical power is partly to blame for a similar issue in the field of neuroscience.

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