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Stat Med. 1992 Jun 15;11(8):1099-102.

Sixteen S-squared over D-squared: a relation for crude sample size estimates.

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Berlex Laboratories, Wayne, NJ 07470.


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.

[Indexed for MEDLINE]

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