Classical Probability
The above table lends itself to describing data another way -- using a probability distribution. Let's consider the frequency distribution for the above sums.
If just the first and last columns were written, we would have a probability distribution. The relative frequency of a frequency distribution is the probability of the event occurring. This is only true, however, if the events are equally likely.
This gives us the formula for classical probability. The probability of an event occurring is the number in the event divided by the number in the sample space. Again, this is only true when the events are equally likely. A classical probability is the relative frequency of each event in the sample space when each event is equally likely.
P(E) = n(E) / n(S)
