title: [Study on the power of O/E method].
abstract: This paper addresses the methodology of calculating the power of O/E method and introduces the relevant algorithm for estimating the sample size. Based on the principles of hyporthesis testing and Poisson distribution, the power can be worked out for given sample size, baseline rate(pi 0) and the factor of increasing (gamma). The power increases with the increase in sample size, pi 0 and gamma. In shape the power is not a continuous smooth line but a zigzag line. The method illustrated in this paper can be also used for estimaging the sample size of studies on the intervention of diseases.
authors.affiliation: Center for Birth Defects Monitoring, Second Affiliated Hospital, Chengdu.
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: F
authors.initials: F
authors.lastname: Chen
authors.forename: C
authors.initials: C
authors.lastname: Kang
authors.forename: S
authors.initials: S
authors.lastname: Yang
mesh_terms: D000013:Congenital Abnormalities / Q000453:epidemiology; D006801:Humans; D016012:Poisson Distribution; D018401:Sample Size; D013223:Statistics as Topic / Q000379:methods*