conditional probability

American  

noun

1. Statistics, Mathematics. the probability that an event will occur under the condition that another event occurs first: equal to the probability that both will occur divided by the probability that the first will occur.

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conditional probability British  

noun

1. statistics the probability of one event, A, occurring given that another, B, is already known to have occurred: written P ( A|B ) and equal to P ( A and B )| P ( B )

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Etymology

Origin of conditional probability

First recorded in 1960–65

Example Sentences

In order to solve Example 3.30 we had to draw upon the concept of conditional probability from the previous section.

From Textbooks • Nov. 29, 2017

The second method is to test if the conditional probability of A given B is equal to the probability of A. Again for simplicity, we can use an already calculated value from above.

From Textbooks • Nov. 29, 2017

Write your answer as a conditional probability statement.

From Textbooks • Sep. 19, 2013

The reader analyzed the problem using conditional probability, which enables you to answer questions of the type "what are the odds of event A happening given that event B has happened?"

From Scientific American • Apr. 15, 2011

A simple example: the conditional probability of having chosen a king card when it’s known that the card is a face card—a king, queen, or jack— is Vs.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos