# Probability of Or

Discussion in 'Probability and Statistics' started by nycmathguy, Jul 7, 2022.

1. ### nycmathguy

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I found this online:

• Definition: Probability of or for mututally exclusive events If two events: E, F are mutually exclusive then the probability of E or F occurring is: P (E or F) = P (E) + P (F) This property applies regardless of how you calculate the probability of E or F. Moreover, the idea extends to more than two events.
1. What is meant by MUTUALLY EXCLUSIVE?
2. Can rephrase the above definition using layman terms?

nycmathguy, Jul 7, 2022
2. ### MathLover1

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1. The meaning of MUTUALLY EXCLUSIVE is being related such that each excludes or precludes the other; also : incompatible.

2.
If two events are mutually exclusive then the probability of both the events occurring at the same time is equal to zero. P(A and B) = 0

If A and B are two mutually exclusive events, then probability of A or B is equal to the sum of probability of both the events.
P(A or B) = P(A) + P(B)

MathLover1, Jul 7, 2022
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3. ### nycmathguy

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I gather that mutually exclusive events happen at the same time.

Sample A

I can sit and talk. Mutually exclusive.

Sample B

Swim and drown are not mutually exclusive.

Yes?

nycmathguy, Jul 7, 2022
4. ### MathLover1

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Mutually exclusive events are events that can not happen at the same time. Examples include: right and left hand turns, even and odd numbers on a die, winning and losing a game, or running and walking.

Non-mutually exclusive events are events that can happen at the same time.

MathLover1, Jul 7, 2022
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5. ### nycmathguy

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Cool. Are my two samples correct?

nycmathguy, Jul 7, 2022
6. ### MathLover1

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I can sit and talk. Non-mutually exclusive.(you can sit and talk at the same time)

Swim and drown is correct

MathLover1, Jul 7, 2022
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7. ### nycmathguy

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Ok. I like this probability stuff. A bit fuzzy but I like it.

nycmathguy, Jul 8, 2022
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