Autori
De Martini, Daniele
Rapallo, Fabio

Titolo
Evaluating the risk in sample size determination.
Periodico
Università degli Studi del Piemonte Orientale 'A. Avogadro' : Facoltà di Economia - Dipartimento di Scienze Economiche e Metodi Quantitativi "SEMEQ" - Quaderni
Anno: 2005 - Volume: 05 - Fascicolo: 96 - Pagina iniziale: 1 - Pagina finale: 26

This paper focuses on the risk of an experiment with random outcome. When the experiment is based on a random sample of size m and the fixed cost of the experiment is K, the risk r becomes the total cost m + K times the probability of an unfruitful experiment. The risk function is presented, and studied for parametric and nonparametric two sample tests. The ethical risk is defined, that is the risk when the experimental units are patients and only the ethical cost m is considered. An intuitive criterion for sample size determination based on relative risk is proposed. Moreover, an objective criterion for a convenient sample size choice is defined. Finally, a simulation study shows the good behavior of pointwise and conservative sample size estimators based on pilot samples, for the two-sample parametric and nonparametric tests.




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