Pub. date: 2008 | Online Pub. Date: November 27, 2007 | DOI: 10.4135/9781412953948 | Print ISBN: 9781412928168 | Online ISBN: 9781412953948 | Publisher:SAGE Publications, Inc.About this encyclopedia
Michael E. Tarter
Samples are often collected in such a way that the exact value of one or more cases is unknown. Such missing information is referred to as censored data . In one source of such censored data, values are known to exceed or fall below some limit. Often, for example, in a study based on the survival times of laboratory animals, a protocol requires that all data be collected within a specified period of time. For an appreciably sized subset of subjects, an exact survival time may not be known, simply because the study ends before the event of interest (such as the animal's death) could be observed. Because the exact survival times for those who lived longer than the length of the study are not known, this illustrates the generation of right-censored data. Another common example occurs when the age of study participants is recorded in exact years for most ...