Probability.txt

Probability is the measure of the likelihood that an event will occur.[1] Probability is quantified as a number between 0 and 1 (where 0 indicates impossibility[2] and 1 indicates certainty).[3][4] The higher the probability of an event, the more certain that the event will occur. A simple example is the tossing of a fair (unbiased) coin. Since the coin is unbiased, the two outcomes ("head" and "tail") are both equally probable; the probability of "head" equals the probability of "tail." Since no other outcomes are possible, the probability is 1/2 (or 50%), of either "head" or "tail". In other words, the probability of "head" is 1 out of 2 outcomes and the probability of "tail" is also 1 out of 2 outcomes, expressed as 0.5 when converted to decimal, with the above-mentioned quantification system.[3][4] This type of probability is also called a priori probability.