The best way to obtain the covariance is by E(XY)-E(X)E(Y), since here x and y are zero quite often.
In fact E(XY)=1/6 since the only time you don't have a zero is when x=y=1.
The joint p.m.f. of X and Y is f(x,y)=1/6, , where x and y are integers.
a) sketch the support of x and y.
b) record the marginal pmfs of and in the margins
c) compute cov(x,y)
d) Determine the correlation coefficient
e) Find the best fitting line.
I am hoping my other answers are correct, but I don't know what they mean for this one. Thank you!