Probability

Probability is a branch of <a href="/facts/Mathematics/pxTouaz4">mathematics</a> and <a href="/facts/Statistics/DNPsKGYU">statistics</a> concerning <a href="/facts/Event_(probability_theory)/aJ0l4oQb">events</a> and numerical descriptions of how likely they are to occur. The probability of an event is a number between 0 and 1; the larger the probability, the more likely an event is to occur. This number is often expressed as a percentage (%), ranging from 0% to 100%. A simple example is the tossing of a fair (unbiased) coin. Since the coin is fair, the two outcomes ("heads" and "tails") are both equally probable; the probability of "heads" equals the probability of "tails"; and since no other outcomes are possible, the probability of either "heads" or "tails" is 1/2 (which could also be written as 0.5 or 50%).
These concepts have been given an <a href="/facts/Probability_axioms/j6IkXsIT">axiomatic</a> mathematical formalization in <a href="/facts/Probability_theory/mFBn51rE">probability theory</a>, which is used widely in <a href="/facts/Areas_of_study/pKoQHpYL">areas of study</a> such as <a href="/facts/Statistics/DNPsKGYU">statistics</a>, <a href="/facts/Mathematics/pxTouaz4">mathematics</a>, <a href="/facts/Science/IJoaD7rs">science</a>, <a href="/facts/Finance/fLh1GgN8">finance</a>, <a href="/facts/Gambling/Hgw4a9DH">gambling</a>, <a href="/facts/Artificial_intelligence/lJGauQwX">artificial intelligence</a>, <a href="/facts/Machine_learning/e0w0XJTu">machine learning</a>, <a href="/facts/Computer_science/lN3pEyPz">computer science</a>, <a href="/facts/Game_theory/zkEIj1ya">game theory</a>, and <a href="/facts/Philosophy/zAH5PVD6">philosophy</a> to, for example, draw inferences about the expected frequency of events. Probability theory is also used to describe the underlying mechanics and regularities of <a href="/facts/Complex_systems/eGG3B1nn">complex systems</a>.

Probability open-in-new

Probability