title: How I do it: sample size calculations.
abstract: Sample size calculations are integral to project design. A description of the underlying theory behind them is set out. Required are the significance level, the power, the clinical difference and the standard deviation. Douglas Altman's nomogram is particularly useful for sample size calculations for comparing independent samples.
authors.forename: J
authors.initials: J
authors.lastname: O'Hara
mesh_terms: D003627:Data Interpretation, Statistical; D006801:Humans; D010036:Otolaryngology / Q000379:methods* / Q000706:statistics & numerical data; D012106:Research / Q000592:standards* / Q000706:statistics & numerical data; D018401:Sample Size; D012494:Sampling Studies