Editing Urn problem (section)

{{Short description|Mental exercise in probability and statistics}}
[[File:Stochastik Bayestheorem Urnenversuch.png|thumb|Two urns containing white and red balls]]

In [[probability]] and [[statistics]], an '''urn problem''' is an idealized [[thought experiment|mental exercise]] in which some objects of real interest (such as atoms, people, cars, etc.) are represented as colored balls in an [[urn]] or other container. One pretends to remove one or more balls from the urn; the goal is to determine the probability of drawing one color or another, 
or some other properties. A number of important variations are described below.

An '''urn model''' is either a set of probabilities that describe events within an urn problem, or it is a [[probability distribution]], or a family of such distributions, of [[random variable]]s associated with urn problems.<ref>Dodge, Yadolah (2003) ''Oxford Dictionary of Statistical Terms'', OUP. {{ISBN|0-19-850994-4}}</ref>