If a random experiment is repeated n times under identical conditions and out of n such trials, m trials are favourable to the occurrence of some event A, then the relative frequency is called the estimate of the probability of occurrence of event A, which is denoted by P (A). If the value of n is taken larger and larger, i.e., as n tends to infinity, the limiting value of the ratio is taken as the probability of occurrence of the event A. Symbolically,

\(P(A)=\lim\limits_{n\to \infty}\,\frac{m}{n}\)