Consider flipping two fair coins. Let X= 1 if the first coin is heads, and X = 0 if the first coin is tails. Let Y= 1 if the two coins show the same thing (i.e., both heads or both tails), with Y= 0 otherwise. Let Z = X + Y, and W =XY.
(a) What is the probability function of Z?
(b) What is the probability function of W?