5. If X is a random variable, we say m is a median if 1 P(X2m)2 and P(X5m)2%. Medians always exist, but in general they need not be unique. However, for continuous dis tributions they generally are unique, and in particular, normals and exponentials have unique medians. (a) If X is normal with parameters ,u, and 0'2, nd the median of X. (b) If X is exponential with parameter A, nd the median of X