Mathematics (2019) Grade(s): 8 - Grade 8 Accelerated

MA19.8A.47

Explain why the conditional probability of A given B is the fraction of B’s outcomes that also belong to A, and interpret the answer in context. [Algebra I with Probability, 41]

COS Examples

Example: the probability of drawing a king from a deck of cards, given that it is a face card, is $\frac{4/52}{12/52}$, which is $\frac{1}{3}$.

Unpacked Content

Knowledge

Students know:
  • Possible relationships and differences between the simple probability of an event and the probability of an event under a condition.

Skills

Students are able to:
  • Accurately determine the probability of simple and compound events.
  • Accurately determine the conditional probability P(A given B) from a sample space or from the knowledge of P(A&B) and the P(B).

Understanding

Students understand that:
  • Conditional probability is the probability of an event occurring given that another event has occurred.

Vocabulary

  • Conditional probability
  • Probability
  • Simple events
  • Compound events
  • Sample space
  • Independent events
  • Dependent events
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