Censoring − Life data are often censored or incomplete in some way. Suppose you are testing how long a certain part
lasts before wearing out and plan to cut off the study at a certain time. Any parts that did not fail before the study ended
are censored, meaning their exact failure time is unknown. In this case, the failure is known only to be "on the right," or
after the present time. This type of censoring is called right censoring.
Similarly, all you may know is that a part failed
before a certain time (left censoring), or within a certain interval of time (interval censoring).