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Math Help - Cumulative distribution function

  1. #1
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    Cumulative distribution function

    We have cumulative distribution function Fx.

    Fx = 1/1000x - 1/4

    How do we get probability density function (gx) from Fx?

    If we have gx, to get Fx, we need to integrate from 0 to x. Am I right?

    So to get gx from Fx, we need to find the derivative, because it's an opposite operation from integration.
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  2. #2
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    Quote Originally Posted by Nforce View Post
    We have cumulative distribution function Fx.

    Fx = 1/1000x - 1/4

    How do we get probability density function (gx) from Fx?

    If we have gx, to get Fx, we need to integrate from 0 to x. Am I right?

    So to get gx from Fx, we need to find the derivative, because it's an opposite operation from integration.
    g(x) = dF/dx.

    By the way, your definition of F(x) is very incomplete, you should have included the values of x for which the given rule applies. As it happens, I doubt very much that what you posted defines a valid cdf.
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    yes i have forgot; the interval is [250,1250]

    I don't completely understand this:

    g(x) = dF/dx.

    What is dF in here? Do you mean the derivative? Can you solve for example above.
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  4. #4
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    Quote Originally Posted by Nforce View Post
    yes i have forgot; the interval is [250,1250]

    I don't completely understand this:

    g(x) = dF/dx.

    What is dF in here? Do you mean the derivative? Can you solve for example above.
    Of course it's the derivative. What else could it possibly be?

    I have no intention of solving it. Surely you know how to find the derivative of a function.
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  5. #5
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    ok, thank you.
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