Life tests are run for various purposes. Tests run to detect the level of infant mortality involve short time
durations; unless the percentage of devi& having infant mortality is extremely high, the sample size
specified in this document is not nearly sufficient. Tests to determine device lifetime for a specific
application may be conducted by or for a customer, here the stress and test conditions may be specific to
the application. Other life tests are run by a manufacturer and are concerned with determining the lifetime of devices under typical or extreme operation.