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In poker, the probability of many events can be determined by direct calculation. This article discusses computing probabilities for many commonly occurring events in the game of Texas hold 'em and provides some probabilities and odds for specific situations. In most cases, the probabilities and odds are approximations due to rounding. When calculating probabilities for a card game such as Texas Hold 'em, there are two basic approaches. The first approach is to determine the number of outcomes that satisfy the condition being evaluated and divide this by the total number of possible outcomes. For example, there are six outcomes (ignoring order) for being dealt a pair of aces in Hold 'em: , , , , and . There are 52 ways to pick the first card and 51 ways to pick the second card and two ways to order the two cards yielding possible outcomes when being dealt two cards (also ignoring order). This gives a probability of being dealt two aces of . The second approach is to use conditional probabilities, or in more complex situations, a decision tree. There are 4 ways to be dealt an ace out of 52 choices for the first card resulting in a probability of There are 3 ways of getting dealt an ace out of 51 choices on the second card after being dealt an ace on the first card for a probability of This value is the conditional probability that second card dealt is an ace given the condition that the first card dealt is an ace. The joint probability of being dealt two aces is the product of the two probabilities: This article uses both of these approaches. The odds presented in this article use the notation x : 1 which translates to ''x to 1 odds against'' the event happening. The odds are calculated from the probability ''p'' of the event happening using the formula: odds = (− ''p'') ÷ ''p'' ) : 1, or odds = (÷ ''p'') − 1 ) : 1. Another way of expressing the odds x : 1 is to state that there is a ''1 in x+1'' chance of the event occurring or the probability of the event occurring is 1/(x+1). So for example, the odds of a roll of a fair six-sided dice coming up three is 5 : 1 against because there are 5 chances for a number other than three and 1 chance for a three; alternatively, this could be described as a 1 in 6 chance or probability of a three being rolled because the three is 1 of 6 equally-likely possible outcomes. ==Starting hands== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Poker probability (Texas hold 'em)」の詳細全文を読む スポンサード リンク
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