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Big Ideas:
The probability that event B occurs given that event A has already occurred is called the conditional probability of B given A.
The conditional probability of B given A is written P(B|A).
Order matters: The conditional probability of B given A is often not the same as the conditional probability of A given B
Students were formally introduced to probability in seventh grade with the standard 7.SP-5. This lesson is an introduction to the concept and computation of conditional probability without using a formula. This lesson builds on the concepts and skills learned during the study of the content related to standards S-CP.1 and S-CP.2. In this particular lesson, students use their knowledge of probability to help understand the concept of independence. This lesson directly builds towards the content in the lessons: "A formula for computing conditional probability" and "Determine whether events are independent by using conditional probability."
Vocabulary: conditional probability, the use of the symbol | as in P(B|A) to denote conditional probability.