title: [What is power and why calculated at 80%?].
authors.affiliation: Abteilung für Strahlentherapie und Radio-Onkologie, Universität Hamburg.
authors.forename: H H
authors.initials: HH
authors.lastname: Dubben
authors.forename: H P
authors.initials: HP
authors.lastname: Beck-Bornholdt
mesh_terms: D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D006801:Humans; D011336:Probability; D018787:Radiation Oncology / Q000706:statistics & numerical data; D013223:Statistics as Topic / Q000379:methods*; D016019:Survival Analysis