\begin{definition}[Definition:Pólya's Urn]
'''Pólya's urn''' is an implementation of an urn such that, when a ball of a particular colour is taken out and examined, that ball is replaced and another of the same colour is added.
{{NamedforDef|George Pólya|cat = Pólya}}
Category:Definitions/Probability Theory
\end{definition}