7. Suppose p(x, y,z), the joint probability mass function of the random variables X, Y , and Z, is given by p(1, 1, 1) = 1 8 , p(2, 1, 1) = 1 4 , p(1, 1, 2) = 1 8 , p(2, 1, 2) = 3 16 , p(1, 2, 1) = 1 16 , p(2, 2, 1) = 0, p(1, 2, 2) = 0, p(2, 2, 2) = 1 4

What is E[X|Y = 2]? What is E[X|Y = 2, Z = 1]?