Survival Analysis I
Survival data are generally not symmetrically distributed—they will often appear positively skewed, with a few people surviving a very long time compared with the majority; so assuming a normal distribution will not be reasonable.
At the completion of the study, some patients may not have reached the endpoint of interest (death, relapse, etc.). Consequently, the exact survival times are not known. All that is known is that the survival times are greater than the amount of time the individual has been in the study. The survival times of these individuals are said to be censored (precisely, they are right-censored).
KeywordsSurvival Time Hazard Function Survivor Function Failure Time Survival Experience
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