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Math Help - [SOLVED] need help on stats, plz!

  1. #1
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    [SOLVED] need help on stats, plz!

    I need help with following questions plz, really appreciate it

    Last edited by mr fantastic; April 2nd 2009 at 08:38 PM. Reason: OP deleted the questions - questions restored and thread closed.
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  2. #2
    MHF Contributor matheagle's Avatar
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    The density is f(y)=1-y on 0<y<1 and f(y)=.5 on 2<y<3.

    Now you need \int_0^3 yf(y)dy and \int_0^3 y^2f(y)dy.
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  3. #3
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    Sorry to bother you again, how do u find and ? can u provide me the solution for the questions? thanks
    Last edited by mr fantastic; April 2nd 2009 at 08:39 PM. Reason: OP deleted the question - question restored and thread closed.
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  4. #4
    MHF Contributor matheagle's Avatar
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    basic calculus one

    \int_0^3 yf(y)dy= \int_0^1 (1-y)ydy + .5\int_2^3 ydy

    and

    \int_0^3 y^2f(y)dy= \int_0^1 (1-y)y^2dy + .5\int_2^3 y^2dy .
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  5. #5
    MHF Contributor matheagle's Avatar
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    The CDF is zero if y<0

    \int_0^y (1-t)dt= y-y^2/2 on 0<y<1

    .5 on 1<y<2

    .5 + .5\int_2^y dt =.5 + .5(y-2)=.5y-.5 on 2<y<3

    and 1 after 3.

    You can put include the endpoints of each interval anywhere you wish.
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