What Is a Conditional Probability?
Conditional probability describes events that affect each other. This means that the probability of one event changes if another event has occurred. is the probability of occurring given that you “know” that has already occurred. You can find it with this formula:
Example 1
In Nick’s class, of the students like sushi, and like both sushi and kebabs. If you know that Nick likes sushi, what is the probability of him also liking kebab?
Let be the event “Nick likes kebab”, and let be the event “Nick likes sushi”. Then you’ll have to find . Using the formula above, you get
which tells you that the conditional probability of Nick liking kebab given that he likes sushi is %.
