One of the meanings of the mathematical theory of probability is "the interpretation of probabilities as relative frequencies, for which simple games involving coins, cards, dice, and roulette wheels provide examples. The distinctive feature of games of chance is that the outcome of a given trial cannot be predicted with certainty, although the collective results of a large number of trials display some regularity." (The New Encyclopeadia Britannica, Volume 26, 15th Edition, 1993, "Probability Theory")