Intended for healthcare professionals


Sample size calculations: should the emperor’s clothes be off the peg or made to measure?

BMJ 2014; 349 doi: (Published 27 August 2014) Cite this as: BMJ 2014;349:g5341

In this Research Methods and Reporting article, a type II error was incorrectly defined in the first paragraph of the section “What α and β levels do you want?” (BMJ 2012;345:e5278, doi:10.1136/bmj.e5278). A type II error should have been defined as: “accepting [not “rejecting” as was published] the null hypothesis when the alternate hypothesis is true.”


Cite this as: BMJ 2014;349:g5341

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