LESSON: Conditional Probability
| Site: | Mountain Heights Academy OER |
| Course: | Introductory Statistics Q4 |
| Book: | LESSON: Conditional Probability |
| Printed by: | Guest user |
| Date: | Saturday, 26 April 2025, 12:41 PM |
Intro to Conditional Probability
A conditional probability is the probability of an event occurring, given that another event has already occurred. The conditional probability of event A occuring, given that event B has occurred is denoted by P(A|B) and is read as "probability of A, given B".
Conditional Probability Rule
Before we generalize the conditional probability rule, it's important for us to get some practice finding "joint" probabilities, or probabilities that include the $$\bigcap$$ symbol, meaning "and".
When looking for joint probabilities, we're looking for two events that occur together. At the beginning of the following lesson video I will go over a few examples of finding joint probabilities. Following that you will see the formal conditional probability rule.
Conditional Probability Examples
In the following lesson video you will see four examples of how to use the conditional probability rule. The hardest part of using the conditional probability rule is identifying which event is "given". This will take practice of logically thinking through what the question is asking.
More Examples
So far, all the examples I have shown you have involved the use of two way tables giving you the possible outcomes. In the next lesson video you will see examples of computing conditional probability where the outcomes are not organized for us in a two way table.