• Example 2.24 demonstrates that when outcomes are equally likely,
    • computation of conditional probabilities can be based on intuition.
  • When experiments are more complicated, though, intuition may fail us,
    • so a general definition of conditional probability is needed that will yield intuitive answers in simple problems.
  • The Venn diagram and Equation (2.2) suggest how to proceed.

conditional probability

For any two events and with , the conditional probability of given that has occurred is defined by P\left( {A \mid B}\right) = \frac{P\left( {A \cap B}\right) }{P\left( B\right) } \tag{2.3}

EX 2.25 buying digital camera

EX 2.26 reading habit