Given XXX is a discrete random variable with P(X=k)=13P(X=k) = \frac{1}{3}P(X=k)=31 for k∈{−1,0,1}k \in \{-1, 0, 1\}k∈{−1,0,1}, what is E[X2]E[X^2]E[X2]?
000
2/32/32/3
111
1/31/31/3