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Homework Help: Implementation of Bayes law(probabilities)

  1. Oct 17, 2004 #1
    Hi guys
    i know that i post a problem without my own answer but this problem is
    very difficult for me and i'm very comfused.
    The exercise says that we must implement the Bayes' Law to solve the exercise.My problem is that i cant distinguish and write down the events ):

    Problem:In my kitchen i put my 10 forks in the left drawer and my 10 knifes in the right drawer.
    before my room mate change something:
    left drawer : (10f,0k)
    right drawer: (0f,10k))

    When my room-mate came he took 2 forks from the left drawer and he put them in the right drawer.

    after my room mate's alteration:
    left drawer : (8f,0k)
    right drawer: (2f,10k)

    After this action he chooses one piece(knife or fork) from the right drawer and he puts the piece in the left drawer.

    left drawer : (9f,0k) or (8f,1k)
    right drawer: (1f,10k) or (2f,9k)

    After all these changes i come and choose one piece from 1 of the 2 drawers.
    IF Is given that i hold a knife,what is the probability that i opened the left drawer?
  2. jcsd
  3. Oct 17, 2004 #2
    apply simple Bayesian Law,
    Let K be the event u pick the knife
    Let L be the event u pick something from the left drawer
    to find,

    simple Bayesian states,
    P(L/K)*P(K) = P(K/L)*P(L)

    can u find P(K),P(K/L),P(L) ??

    -- AI
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