Let X, X,,..., X, be random sample of size n that distributed according to exponential distribution with mean a) Explain why is not a pivotal quantity? (Note that is the maximum order statistic). b) Explain why Q= statistic). is a pivotal quantity? (Note that is the 1st order (15 marks) c) Based on the pivotal quantity, derive the 90% confidence interval for 0. (Identify values of a and b in the confidence interval). (10 marks)