申論題

5. (10%) Consider the shift exponential distribution
f(x) = λ•e^-λ(x-θ)where x ≥θ

When θ = 0, the density reduces to the usual exponential distribution. When θ ＞ 0, there is only positive probability to the right of θ.

(a) Find the maximum likelihood estimation (MLE) of λ, based on a random sample size n?