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vikkisut88
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Homework Statement
Let X be a random vairable which can only take three values: -1,0,1 and they each have the same probability. Let Y also be a random vairable defined by Y = X2. Show that
i) X and Y are not independent
ii) X and Y are uncorrelated
Homework Equations
To show that two random variables are independent, you show that E(XY) /= E(X)E(Y)
To show that two random variables are uncorrelated, you show that [tex]\rho[/tex]x,y = 0
The Attempt at a Solution
I have found E(X) = 0 and E(Y) = 2/3 and so E(X)E(Y) = 0, however i don't know how to calculate E(XY) as I don't know how to construct the joint probability mass function table for X and Y