A nonparametric asymptotic confidence interval for the median survival time is developed for the case where data are subject to arbitrary right censoring. This is accomplished by inverting a generalization of the sign test for censored data. A simulation study shows that this nonparametric confidence interval performs well for a variety of underlying survival functions. The procedure is applied to data from a clinical trial that compared four dosage regimens of 5-fluorouracil.

Biometrics is a scientific journal emphasizing the role of statistics and mathematics in the biological sciences. Its object is to promote and extend the use of mathematical and statistical methods in pure and applied biological sciences by describing developments in these methods and their applications in a form readily assimilable by experimental scientists. JSTOR provides a digital archive of the print version of Biometrics. The electronic version of Biometrics is available at http://www.blackwell-synergy.com/servlet/useragent?func=showIssues&code;=biom. Authorized users may be able to access the full text articles at this site.

The International Biometric Society is an international society for the advancement of biological science through the development of quantitative theories and the application, development and dissemination of effective mathematical and statistical techniques. The Society welcomes as members biologists, mathematicians, statisticians, and others interested in applying similar techniques.