Revista brasileira de psiquiatria : orgão oficial da Associação Brasileira de Psiquiatria, Asociación Psiquiátrica de la América Latina
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The authors present the basic concepts in epidemiology and statistics needed for understanding properly the design and results of controlled clinical trials. Through a set of examples, the concepts of measures of association and effect, statistical significance tests, p-value, confidence interval and statistical power are presented and common their misinterpretations are discussed.