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# Statistics › Probability theory: Glossary

## Conditional Probability

In probability theory, the probability of some event A, assuming event B. Conditional probability is written `P(A|B)`, read "the probability of A, given B". The probability of getting a Jack given a face card, is an example of event with conditional probability - its probability depends on the probability of picking a face card out of the deck in the first place. Conditional probability canbecalculated using Bayes theorem: `P(A|B) = P(B|A)P(A)/P(B)`

## Elementary Event

(also: *atomic event*, *sample point*)\
In probability theory, an elementary event is an event which contains only a single outcome in the sample space. For example, getting the 2 of ❤ when picking a card from a deck is an elementary event, while getting a face card (any suit JQK) is not.