In reality, events are often not independent. If an earthquake happens in Japan, this may affect the probability of a certain political party getting elected. It is in these situations of conditional probability that the topic of probability starts to get a lot more interesting.

The probability that one event occurs given that another event has occurred is expressed by the following formula:

Example

Exercise

Let’s complete exercise 6 from pages 382 and 383 of the extended textbook:

The answers are below: