. Let X1, , Xn be i.i.d. with exponential density function f(x|) = (1 /) (e ^(x/))for x > 0 and f(x|) = 0 otherwise, where the parameter is unknown

• . Show that the maximum likelihood estimator (MLE) = X, the sample mean.
• Define = 2 . What is the MLE of ?
• By the delta-method, derive the central limit theorem of