Suppose that we know that the random variable X follows the PDF given below: f(x | a, y) = Yay-1 -exp for x > 0; a, y > 0 Given a sample of n i.i.d observations x = (X1, . . ., In) from this distribution, please answer the following questions: (a) Find maximum likelihood estimator for the parameter o, assuming y is a constant and not a parameter. [4.5 marks] (b) If you are going to use a small sample data to calculate an estimate of o to specify a single plug-in distribution, explain whether you can do it using the form you got in (a)