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Cumulative Distribution Function problem

  1. Oct 19, 2011 #1
    1. The problem statement, all variables and given/known data
    Let the independent random variables X1,X2,X3 have the same cdf F(x). Let Y be the middle value of X1,X2,X3. Determine the cdf of Y.

    2. Relevant equations

    F(x) = P(X<=x) = ∫-inf to x f(y)dy

    3. The attempt at a solution

    I don't understand the question, what does it exactly mean when Y is the middle value of X1,X2,X3? I'm not exactly sure where to start. Can somebody help?
  2. jcsd
  3. Oct 19, 2011 #2


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    Science Advisor

    If one sample is [itex]X_1= -5[/itex], [itex]X_2= 3000[/itex], [itex]X_3= 500[/itex], then Y is the "middle value", 500. 500 is the "middle value" because -5< 500< 3000.
  4. Oct 19, 2011 #3
    Oh.. Ok

    I'm still a bit lost on how to tackle this problem..:confused:
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