4. Let X have a normal distribution with mean a and varianoe 0'2 and let Y = ex . Y is said to have a lognormal distribution with parameters is and 02 (since X = log\") has a normal distribution). (a) Find the density fy {y}. (Hint: compute FY (y) = P[Y <_z y find the mean and variance of y. : if x w n01 then e fpt let x1 x2 . be a random sample size n from distribution f with p. _ number th less or equal to as ac i g :1: otherwise is empirical function it used estimate f. show that fli fn an unbiased estimator hint: zi-="I" bernoulli variable parameter p="F(:i:)" var mat asymptotic mam fm fem why do not need give proof you only quote theorem>