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Joint probability mass function

  1. Mar 10, 2015 #1
    I'm having difficulties reading this, could someone please explain to me?

    2 coins
    Ω = {HH, HT, TH, TT}
    0 = Tails
    1 = Heads
    PX,Y(x,y) = P({TT} n {HH}) for (x,y) = (0,0)
    P({HH, HT,TH} n {HH}) for (x,y) = (1,0)
    P({TT} n {TT, TH, HT}) for (x,y) = (0,1)
    P({HH,HT,TH} n {TH,HT,TT}) for (x,y) = (1,1)
    0 otherwise

    PX,Y(x,y) = P(0) for (x,y) = (0,0)
    P({HH}) for (x,y) = (1,0)
    P({TT}) for (x,y) = (0,1)
    0 otherwise
    PX,Y(x,y) = 0.25 for (x,y) = (1,0)(0,1)
    0.50 for(x,y) = (1,1)
    0 otherwise

    That's basically the lay out i was given.
    im not sure how to read for(x,y) = (0,0) and the others similar to it.

    Solved it thank you, if anyone is curious i forgot to mention that X = 0 if the outcome equals to TT and if X = 1 for the outcome if it equals to HH HT TT..
    Y = 0 if the outcome is equal to HH
    Y = 1 if the outcome is equal to HT TT TH
    Last edited: Mar 10, 2015
  2. jcsd
  3. Mar 15, 2015 #2

    Stephen Tashi

    User Avatar
    Science Advisor

    If your question is about how to read notation, the way you have presented the notation isn't coherent. For example, I think you are using "n" to mean the intersection symbol [itex] \cap [/itex].

    If this notation comes from a problem, I suggest you post the problem in the homework section and quote the entire problem exactly.

    Perhaps you can use LaTex: https://www.physicsforums.com/help/latexhelp/
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