Let $X1,X2,.....,Xn$ be iid Poisson random variables with unknown parameter $p>0$. Find the minimum variance unbiased estimator of $e^(-2p)$.
I could find two estimators, one by the method of the Cramer Rao and another method by the MLE, do I compare only the MLEs of the two method. Also, the cramer rao lower bound for variance in this case is not achieved.