Conditional Probability

Conditional probability is the probability of some event Math formula , given the occurrence of some other event Math formula . This is denoted Math formula and is read “the probability of Math formula , given Math formula ”. In other words, we are calculating probabilities conditional on knowing further information partway through the experiment.

     Math formula


A math teacher gave her class two tests. Math formula of the class passed both tests and Math formula of the class passed the first test. What percent of those who passed the first test also passed the second test?

Math formula

Two-thirds or approximately Math formula of the class passed the second test.


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