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Disjoint and Overlapping Events, a la Shmoop It’s a little known fact that most Pirates

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miss their mommies.

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That’s why every Friday night they kidnap a mommy and roll dice to see who gets to be

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read a bedtime story. To play this dice game, the pirates have to

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know a little something about Disjoint Events.

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Disjoint Events cannot both occur at the same time. If one happens, the other doesn’t.

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If a pirate is flying in the air, he is not swimming underwater at the same time.

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Disjoint Events are also described as Mutually Exclusive, because the occurrence of one excludes

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the occurrence of the other.

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Another type of Disjoint Event is a Complementary Event. This is when one event occurs if and

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only if the other event does not.

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For example, a pirate flips a doubloon. If it is not tails, it must be heads, because

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the events are complementary. Overlapping events are events that have one

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or more outcomes in common.

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For example, if a pirate walks into the bar, there’s a possibility he could be missing

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both a leg and an eye. Back to the dice game. Let’s test your pirate

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jargon.

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How would you describe these events:

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Rolling a die and getting an odd number or a 4. Note that the weird bar sign isn't a

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typo, that bar sign is just another way for mathematicians to write "or."

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They are mutually exclusive, because a 4 cannot be an odd number.

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How about rolling a die and getting an odd number or an even number?

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They are both mutually exclusive and complementary, because if you don’t get an even number

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you get an odd number, and vice versa.

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And finally, rolling a die and getting an even number or a four.

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They are neither mutually Exclusive nor Complementary. They are overlapping events, though.

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Well, looks like this Friday will end like all pirate Fridays.

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Nobody understands the convoluted rules of the dice game, so they untie Mommy and have

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a big dance party instead.

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