The theory of probability becomes of enhanced value to gamblers when it is used with the law of large numbers. The law of large numbers states that:
So far we have discussed probabilities in terms of outcomes either occurring or not occurring, but sometimes the gambler will wish to know the probability of an outcome occurring within a given time or during a given sequence of events.
Converse (complementary) probabilities
Converse – "Something that has been reversed; an opposite."
Independent or mutually exclusive event?
One of the important steps you need to make when considering the probability of two or more events occurring. Is to decide whether they are independent or related events.