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Homework Help: PROBABILITY: Distribution function

  1. Nov 14, 2011 #1
    1. The problem statement, all variables and given/known data
    A continuous random variable X has density f(x) = ax2(1- x) for 0 < x < 1, and
    f(x) = 0 otherwise. Here a is a constant, to be determined. Find the distribution func-
    tion FX, the constant a, the expectation E(X), the variance Var(X), and the conditional
    probability p(X < 1/2 | X > 1/4)



    2. Relevant equations



    3. The attempt at a solution
    Really dont know where to start
     
  2. jcsd
  3. Nov 14, 2011 #2

    LCKurtz

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    Gold Member

    Start by using the fact that
    [tex]\int_{-\infty}^\infty f(x)\,dx=1[/tex]
    to figure out a. Then use the standard formulas.
     
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