Conditional Probability

  1. What is the textbook's definition of probability?
  2. If there are 8 green marbles and 4 red marbles in a bag, and you were asked to draw one without looking, what is the probability of drawing one green marble?
  3. If you don't put that green marble that you drew in #2 back in the bag, now what is the probability of drawing another green marble?
    In §4.4 we are introduced to the concept of conditional probability. The notation P(A | B) denotes the probability of event A occurring given that we know event B has occurred. That’s the definition.