b) and c) please f(z)=1/2exp{-|z|}, NOT f(z)=exp{-1/2|z|}.

4 The positive random variable X is said to be a lognormal random variable with parameters ,u and 02 if log(X) is a normal random variable with mean p and variance :72. 3.) Use the normal moment generating function to nd the mean and variance of a lognormal random variable. b) Given the density function 12(2) = scum-gel}, -00