(a) Let A={1,2,…,n} for some n∈N and S=2^A be the power set of A. Define P(s) = 1/ |S| for all s∈S. Let X be the random variable given by X(s) = |s| for each set s∈S. Show that E(X)=n/2.

(b) Let X be a random variable whose value is never 0. Prove or disprove:  1/E(X) = E(1/X)