Long-Run Relative Frequency

N 趨近於無限大時, Relative frequency 會趨向穩定, 則此極限用來定義事件發生的機率

We define P(A), the probability of an event A, as the value to which the relative frequency stabilizes with increasing number of trials. Although we will never know P(A) exactly, it can be estimated accurately by repeating the experiment many times.