Author(s): Lehr R
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Abstract I suggest for memorization an equation for calculating approximate sample size requirements intended only for a specific set of values (80 per cent power for a two-tailed alpha = 0.05 test) which seems to occur often in biopharmaceutical research. After presenting the formula in terms of variance estimate s2 and effect size d, I derive a few alternative forms and then discuss the accuracy of the approximation and other properties as well as examples of its use.
This article was published in Stat Med
and referenced in Journal of Biometrics & Biostatistics