Conditional probability

Conditional probability

Lessons

Notes:
\cdot P(B | A): probability of event B occurring, given that event A has already occurred.

\cdot recall: P(A and B) = P(A) \cdot P(B | A)
then: P(B | A) = P(AandB)P(A)\frac{P(A\;and \;B)}{P(A)}
  • 2.
    Probability Tree Diagram
    Bag A contains 2 red balls and 3 green balls. Bag B contains 1 red ball and 4 green balls.
    A fair die is rolled: if a 1 or 2 comes up, a ball is randomly selected from Bag A;
    if a 3, 4, 5, or 6 comes up, a ball is randomly selected from Bag B.
Teacher pug

Conditional probability

Don't just watch, practice makes perfect.

We have over 1270 practice questions in AU Maths Methods for you to master.