Suppose that X and Y are random variables such that E(Y | X) = 7 - (1/4)x and E(X | Y) = 10 - Y . Determine the correlation of X and Y .
Edit:
So far I've got
E(x)=4 E(y)=6
Now I'm trying to find
E(xy) to use in cov(x,y)=E(xy)-E(x)E(y)
V(x)
V(y)
all to use in cor(x,y)=cov(x,y)/(v(x)v(y))^.5