Betting odds are expressed in the form r:s corresponding in theory to a probability of of winning. In reverse, if p is the probability of an event happening, the odds on it will be p:(1−p). In practice, odds offered by a bookmaker will only be an approximation to this probability, as the bookmaker wishes to make money and will change the odds to reflect the amount of money being bet on particular events even if they have no reason to change their view of the probabilities of those events.
If the probability of an event happening is p, then the odds on that event happening (as opposed to it not happening) are
If the odds are expressed as a simple fraction m/n, where m and n are positive integers, then the probability of the event happening is
In the case m>n the odds are said to be ‘m to n on’. In the case m<n the odds are said to be ‘n to m against’. Thus, for example, if then the odds are ‘4 to 1 on’, and if then the odds are ‘4 to 1 against’. Confusingly, in the case the odds are said to be ‘evens’!
The ratio of the probability that an event occurs to the probability that it does not occur. The ratio of two odds, known as the odds-ratio, is used especially in the comparison and modelling of conditional probabilities.
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- SEO
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- SEPA
- sepal
- separable first-order differential equation
- separable(of a function)
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- 10/100/1000 Base-T
- 10 Base 2
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- 10 Base FX