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Math Help - PDF and CDF

  1. #1
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    PDF and CDF

    Let X be a continuous random variable with PDF fX(x) = ce^{-|x|}

    Let Y = |X|. Find the CDF of Y and deduce its PDF

    I have gotten 1-e^-y for y>=0 as the cdf

    someone showed me what they got which is sinhy;The problem that i see with this is that we need limit as the CDF approaches 0 to be zero which this fulfils, but also the limit as the cdf approaches infinity to be one which this does not fulfil. Anyway if someone could check what they get as a solution i would appreciate it.
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    Quote Originally Posted by ulysses123 View Post
    Let X be a continuous random variable with PDF fX(x) = ce^{-|x|}

    Let Y = |X|. Find the CDF of Y and deduce its PDF

    I have gotten 1-e^-y for y>=0 as the cdf Mr F says: I get this too.

    someone showed me what they got which is sinhy;The problem that i see with this is that we need limit as the CDF approaches 0 to be zero which this fulfils, but also the limit as the cdf approaches infinity to be one which this does not fulfil. Anyway if someone could check what they get as a solution i would appreciate it.
    To specify the cdf completely you need to add that cdf = 0 for y < 0.
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