2. 4 PROBABILITY The classical or a priori definition if an experiment can result in n mutually exclusive and equally likely outcomes and if m of these outcomes are favorable to event a then P(A, the probability that A occurs, is m/n P(4)= the number of outcomes favorable to a the total number of outcomes Two features of the probability (1) The outcomes must be mutually exclusive: (2) Each outcome must have an equal chance of occurring.2.4 PROBABILITY • 1．The Classical or A Priori Definition：if an experiment can result in n mutually exclusive and equally likely outcomes, and if m of these outcomes are favorable to event A, then P(A), the probability that A occurs, is m/n Two features of the probability: （1）The outcomes must be mutually exclusive; （2）Each outcome must have an equal chance of occurring. the total number of outcomes the number of outcomes favorable to A ( ) = = n m P A