PROBABILITY

It is confidence which we express in the highly of a thing whose occurrence in a certain situation is uncertain.
Probably of occurrence of an event is a real number which lies between zero and one inclusive if the event does not occur its probability is zero and the event to certain to occur its probably of occurrence is one.
if in events occur its probability of occurrence is called the probability of success. which is denoted by "p" the probability of non occurrence of an event is called probability of failure which is denoted by "q" where p+q =E+p =1 if there are total "n" equally likely and mutually exclusive possibilities in a random experiment and if an event "A" occurs in "m" number of equally ways than the probably of success of event A is given by p(A)= p= m/n and the probably of failure of event "A" will be p(A') =n-m/n=1-m/n=1-p(A)=1-p.
The definition of probability of success of event "A" is called classical or priory definition which mainly defends on a condition that all the possibilities is a particular random experiment are equal likely and mutually exclusive it shows that if the possibilities are not equally and mutually exclusive we cannot give on estimate of the probably of success of an event of interest.