Biometrics is a scientific journal emphasizing the role of statistics and mathematics in the biological sciences. Its object is to promote and extend the use of mathematical and statistical methods in ...

Power analyses and sample size calculations are important parts of many research projects. Often, before data are even collected, it is necessary to calculate and justify the required sample size for ...

The selection of suitable outcomes and sample size calculation are critical factors in the design of a randomised controlled trial (RCT). The goal of this study was to identify the range of outcomes ...

Cheung and colleagues warned that underpowered studies that committed a type II error will discourage clinicians from using effective treatment.1 I agreed with this ...

For a desired power of detecting the association between a disease and several potential risk factors in case-control studies, Yang (1978, Biometrika 65, 635-640) and Halperin (1980, Biometrika 67, ...