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Math Help - probability of A given B.

  1. #1
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    probability of A given B.

    HI; Just need to check if this is correct,Whats the probability of A given B?

    P(A) = 1/2
    P(B) = 1/2
    P(A | B) = P(AB) / P(B).
    P(AB) = P(A) + P(B) - P(A B).
    = 3/6 + 3/6 4/6.
    = 6/6 - 4/6.
    = 2/6 = 1/3.

    P(A | B) 1/3 / 3/6 = 1/3 * 6/3 = 6/9.
    = 2/3.

    Thanks.
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  2. #2
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    Re: probability of A given B.

    Quote Originally Posted by anthonye View Post
    HI; Just need to check if this is correct,Whats the probability of A given B?

    P(A) = 1/2
    P(B) = 1/2
    P(A | B) = P(AB) / P(B).
    P(AB) = P(A) + P(B) - P(A B).
    = 3/6 + 3/6 4/6.
    If all you were given is that "P(A)= 1/2" and "P(B)= 1/2" (above) where did you get " P(A\cap B)= 4/6?

    = 6/6 - 4/6. = 2/6 = 1/3.

    P(A | B) 1/3 / 3/6 = 1/3 * 6/3 = 6/9.
    = 2/3.

    Thanks.
    Follow Math Help Forum on Facebook and Google+

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