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Probability Question about CDFs

  1. Nov 8, 2009 #1
    Just wondering if someone could help me out on a problem. i mean PDFs, not CDFs in the title. Soz

    Thanks in advance.

    <_ means greater and equal to

    Well, if we give Z to be a random varible with a pdf of:

    pdf of Z = (5/2)*z^3 if -1<_ z _> 1
    0 otherwise

    Suppose that X = 2-Z^2

    What is the pdf of X?
  2. jcsd
  3. Nov 8, 2009 #2


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    what do you think? the idea is to have a go and get some help with your work...
  4. Nov 9, 2009 #3
    well if i first find the CDF of FX(x) then um, try plugging it in to find the probablility of y<_y?
  5. Nov 9, 2009 #4


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    The notation [tex] -1 \le z \ge 1 [/tex] doesn't make any sense. do you mean [tex] -1 \le z \le 1 [/tex]?
  6. Nov 9, 2009 #5
    yes i do mean [tex]
    -1 \le z \le 1

    can u help me on the question?
  7. Nov 9, 2009 #6


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    ok so what is y & what do you plan to "plug-in"?

    Based on the question, I would use the known CDF/PDF of Z and try & use it to calculate that of X
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