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kingwinner
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Homework Statement
X and Y are joointly distributed discrete random variables with probability mass function
pX,Y(x,y)=(c/ec)(1-c)xcy/y!, x,y=0,1,2,..., 0<c<1
Find E(XY)
Homework Equations
The Attempt at a Solution
Code:
By definition,
E(X[SUP]Y[/SUP])
∞ ∞
= ∑ ∑ x[SUP]y[/SUP] (c/e[SUP]c[/SUP])(1-c)[SUP]x[/SUP]c[SUP]y[/SUP]/y!
x=0 y=0
Thanks for any help!