Certification Models
Sampling model.  Software testing executes m random
test cases and is certified if no failures or a specified
numbers of failures occur. The value of m is derived
mathematically to ensure that required reliability is
Component model.   A system composed of n
components is to be certified. The component model
enables the analyst to determine the probability that
component i will fail prior to completion.
Certification model.  The overall reliability of the system
is projected and certified.