The case against retrospective statistical power analyses with an introduction to power analysis

摘要

Statistical power analysis is an important tool for planning an experiment because this type of analysis allows researchers to identify an appropriate sample size for a particular experimental design. In recent years, it seems many biology journals (see Table 1 in Hoenig and Heisey 2001) have been encouraging researchers to calculate statistical power after their experiments when they have obtained non-significant results (hereafter, termed "retrospective power calculation or analysis" as opposed to "prospective power analysis", which is conducted pre-experimentally).