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Homework Help: Probability unions

  1. Sep 14, 2011 #1
    Have a problem that I've worked through, would appreciate any feedback on it to tell if I'm doing it correctly:

    Say the probability of success is .95. Two different actors, acting independently:
    1. Probability that both actors are successful: I had P(A intersect B) = P(A) * P(B) = (.95)*(.95) = .9025

    2. Probability that neither actor is successful? Was a little confused on this one, but I thought it would be P(A U B)'. In (3), I'd calculated the P(A U B) to be .9975, so 1-.9975 = .0025

    3. Probability that either actor is successful? I used P(A U B) = P(A) + P(B) - P(A intersect B) = .9975

    thank you much.
     
  2. jcsd
  3. Sep 14, 2011 #2
    Looks pretty good to me!
     
  4. Sep 14, 2011 #3
    Looks ok!!

    May I suggest another method for (2)?? The chance that an auther is not succesful is 0.05. so the chance that neither author iss succesful is 0.05*0.05 by independence.
     
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