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November 26th, 2017, 05:49 AM   #1
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Joint probability density question:

The joint random variables have a density

\[f(x,y)=x+y\] for 0<x<1 and 0<y<1 and 0 otherwise, Evaluate E(X) and E(XY)

My answer for E(x)=7/12
however i feel like i may have made a mistake somewhere.

Last edited by Jaket1; November 26th, 2017 at 06:28 AM.
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November 26th, 2017, 06:50 AM   #2
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for E(XY) i got 1/3
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November 26th, 2017, 11:13 AM   #3
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$E[X]=\dfrac {7}{12}$ is correct

Do you see any reason $E[Y] \neq E[X]$ ?

$E[X Y] = \dfrac 1 3$ is also correct.
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