Let X be a random variable with the following probability density function (z-In 4)² fx(x) = √20 2 ≤ In 4 Ae-Az a> ln 4 where σ and A are some positive constants and E[X] = In 4. (a) Determine the value of X? (b) Determine the value of o? (c) Determine variance of the random variable X? (d) Determine the CDF of the random variable X in terms of elementary functions and the CDF of a standard normal random variable?