How to Figure Out Mutually Exclusive Events

Probability 4 Comments

Often in elementary statistics, you’ll be asked to figure out if events are mutually exclusive. That means if one event happens, the other cannot happen.

Sample problem: “If P(A) = 0.20, P(B) = 0.35 and (P U B) = 0.51, are A and B mutually exclusive?”

The answer takes just a couple of simple steps.

Mutually exclusive events

Step 1: Add up the probabilities of the separate events (A and B). In the above example:
.20 + .35 = .55

Step 2: Compare your answer to the given “union” statement (A U B).  If they are the same, the events are mutually exclusive. If they are different, they are not mutually exclusive.

In our example, 0.55 does not equal 0.51, so the events are not mutually exclusive.

Related posts:

  1. How to Find the Probability of Two Events Occuring Together
  2. How to Figure out a Normally Distributed Probability Question Using the TI-89
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4 Responses to “How to Figure Out Mutually Exclusive Events”

  1. Donna Allen said:

    Sep 19, 09 at 9:44 am

    So far, I am finding the explanations given in the blog to be much more helpful than the book. I think things are better explained in better detail here.

  2. Christine Mao said:

    Sep 20, 09 at 8:33 pm

    I honestly think that this blog is very useful and very clear in explaining mutually exclusive event. The book didn’t really explain much and I was kind of confused.

  3. Kalynn Grabau said:

    Sep 21, 09 at 8:48 am

    Again, I absolutely agree with Donna in that this blog makes understanding so much easier than the actual book. I don’t know why, but I’m understanding even more through this blog. Thank you thank you thank you!!

  4. Lisa Barcomb said:

    Nov 12, 09 at 7:31 pm

    Yeah I would agree with the statements above the blogs do tend to be more of a learning material then the book. The book to me just doesn’t give any good examples and when it does it doesn’t explain anything clear.

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