Back to Find conditional probability from a model — Problem 2 · Task Set 23

Exercises: Find Conditional Probability as the Fraction of B's Outcomes That Are Also A

Work through each section in order. To find P(A | B), restrict to B's outcomes first, then count how many of them are also in A: the denominator is the number of B's outcomes, NOT all outcomes. Write probabilities as fractions in lowest terms unless asked otherwise, and interpret each conditional probability with a sentence: "among the B's, this fraction are A."

Grade 10·20 problems·~32 min·Common Core Math - HS Statistics and Probability·group·hss-cp-b-6

Work through problems with immediate feedback

Warm-Up: Sample Spaces and the Conditional Formula

These problems review ideas you already know from Cluster A.

Recall the conditional-probability formula from HSS.CP.A.3. For events $A$ and $B$ with $P(B) > 0$ , which expression equals $P(A \mid B)$ ?

$\dfrac{P(A \text{ and } B)}{P(B)}$

$\dfrac{P(A \text{ and } B)}{P(A)}$

$P(A) \cdot P(B)$

$\dfrac{P(B)}{P(A \text{ and } B)}$