Now we will look at two other types of compound events. In the previous section you worked with finding the probability of multiple events that were "and" statements. What is the probability of of A and B occurring? Now we will work with "or" statements. What is the probability of of A or B occurring?
There are two way that this can occur. Lets say we are finding the probability of students in your class with long hair or short hair. The students will have one or the other. Since the two events will not overlap they are Mutually Exclusive Events.
Now lets find the probability of students who have long hair or blue eyes. These two events can overlap and are called Inclusive Events.
There are two way that this can occur. Lets say we are finding the probability of students in your class with long hair or short hair. The students will have one or the other. Since the two events will not overlap they are Mutually Exclusive Events.
Now lets find the probability of students who have long hair or blue eyes. These two events can overlap and are called Inclusive Events.
Since the two events do not overlap, you simply add the probability of the two events occurring to find the combined probability.
P(long hair) + P(short hair) Watch the two videos for exclusive and inclusive events and copy the rules.
|
To find the probability of an inclusive event you still need to add the probability of the two events occurring. However, since there can also be students with both long hair and blue eyes, you will need to subtract the probability of both occurring from the sum of the two events.
P(long hair) + P(short hair) - P(long hair and blue eyes) |
Complete the following Khan Academy Skills.