Thus if expressed as a fraction with a numerator of 1, probability and odds differ by exactly 1 in the denominator: a probability of 1 in 100 (1/100 = 1%) is the same as odds of 1 to 99 (1/99 = 0.0101. In mathematical terms, where p is the probability of the outcome:
Odds also have a simple relation with probability: the odds of an outcome are the ratio of the probability that the outcome occurs to the probability that the outcome does not occur. Odds are commonly used in gambling and statistics. They are calculated as the ratio of the number of events that produce that outcome to the number that do not. In probability theory, odds provide a measure of the likelihood of a particular outcome. Look up odds in Wiktionary, the free dictionary.
