Editing Urn problem (section)

== Basic urn model ==

In this basic urn model in [[probability theory]], the urn contains ''x'' white and ''y'' black balls, well-mixed together.  One ball is drawn randomly from the urn and its color observed; it is then placed back in the urn (or not), and the selection process is repeated.<ref name="StatisticsHowTo">[https://www.statisticshowto.com/urn-model/ Urn Model: Simple Definition, Examples and Applications — The basic urn model]</ref>

Possible questions that can be answered in this model are:
* Can I infer the proportion of white and black balls from ''n'' observations? With what degree of confidence?
* Knowing ''x'' and ''y'', what is the probability of drawing a specific sequence (e.g. one white followed by one black)?
* If I only observe ''n'' balls, how sure can I be that there are no black balls? (A variation both on the first and the second question)