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Homework Help: Calculating the marginal density function

  1. Aug 12, 2012 #1
    1. The problem statement, all variables and given/known data
    Let f(x,y) = 24xy where x=[0,1], y=[0,1], x+y=[0,1]
    Find E[X] and E[Y]

    2. Relevant equations
    E[X] = the integral from neg. infinity to positive infinity of x * f_X(x) dx where f_X is the marginal density function of X.

    3. The attempt at a solution
    f_X is found by integrating f(x,y) in terms of dy over the span of neg. infinity to positive infinity.

    For the integral, I used the boundaries 0 and 1. Solution guides online suggest that the marginal density function f_X is equal to 24x.
  2. jcsd
  3. Aug 13, 2012 #2

    Ray Vickson

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    Homework Helper

    So, what did YOU get for f_X(x)? Show all your work.

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