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Another joint density problem

  1. Jun 20, 2012 #1
    it seems that i cant understand the boundaries...
    the joint density function:

    f(u,v)= a , u^2 <= v <= 1
    0 , else

    find a

    i just don't know how to start.
    any help ?
    thx
     
  2. jcsd
  3. Jun 20, 2012 #2

    tiny-tim

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    welcome to pf!

    hi wuid! welcome to pf! :smile:

    (try using the X2 button just above the Reply box :wink:)

    let's see :rolleyes: … that's a shelf of height a whose shape is a rectangle with a parabola cut out of it …

    ok, you need it to have total probability of 1 :smile:
     
  4. Jun 20, 2012 #3
    hi !
    thx for the quick reply ,

    let's see if i got u ,

    [itex]\int^{1}_{-1}\int^{1}_{u^{2}}advdu=1[/itex]

    so [itex]a=\frac{3}{4}[/itex]

    is that right ?
     
  5. Jun 20, 2012 #4

    tiny-tim

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    looks good! :smile:
     
  6. Jun 20, 2012 #5
    can you please guide me with two more section in this problem ,
    related to marginal functions & covariance ?

    and i'll leave you for good :)

    i
     
  7. Jun 20, 2012 #6

    tiny-tim

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    i'm not much good at statistics :redface:

    can you start a new thread? :smile:
     
  8. Jun 20, 2012 #7
    o.k i'll start a new one later.

    first i'll try harder... :)
     
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