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Updated: Oct 23, 2026
Assessing Differences in Sperm Competitive Ability in Drosophila
Published on: August 22, 2013
How large should my study be so that I can detect an altered sex ratio?
1Biomedical Sciences Division, Lawrence Livermore National Laboratory, University of California, Livermore 94550.
Abstract:
The world literature on manipulations purported to alter the gender of offspring is a quagmire full of reports presenting inadequate data and contradictory conclusions. Many are due to inappropriate statistical design or analysis. The authors present simple, nontechnical reference tables for determination of the minimum sample size necessary to detect a change in sex ratio (1) from a theoretical value, and (2) between two experimental populations. Simple methods for analyzing the results of gender manipulation experiments are described. Technical details are included in a separate section.
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