Lesson Plan

Compute P(A | B) in a uniform model by restricting to B's outcomes and finding the fraction of them that also belong to A

Connect the counting approach, |A and B| / |B|, to the formula P(A and B) / P(B) from HSS.CP.A.3, explaining why they agree

Find conditional probabilities from sample-space lists, Venn diagrams, and two-way tables by restricting to B

Interpret each conditional probability in terms of the model and its context

Explain that conditioning on B changes the effective sample space to B, so the denominator is the number of B's outcomes

HSS.CP.B.6

HSS.CP.B.6: Find the conditional probability of A given B as the fraction of B's outcomes that also belong to A, and interpret the answer in terms of the model.