## ABSTRACT

Probability, to anyone who deals with concrete ideas of whether a part or system will function, is not an exact science. Even after a probability is calculated it is not certain exactly what information the individual has to work with or needs. We start our discussion with

(2.1)

Now P(A) is probability of A even occurring N is total number of events in which A can be the outcome nA is the number of events in which A is the outcome.