Exercise 7. (Mark 7) The data of annual salaries of graduate students have a mean of $60,000 and a standard deviation of $16,000. Let X be the Random Variable defining the salary of new graduate student. a) Is it possible to approximate the Random Variable X by a Normal Distribution? Justify briefly! b) If X by a Normal Distribution, provide its density function c) If X by a Normal Distribution, provide its standard form Z d) If X by a Normal Distribution, what the probability is for a student to earn strictly less than $50,000; (X