1. The problem statement, all variables and given/known data I am given a data set known to come from a poisson distribution. 2. Relevant equations Poisson distribution 3. The attempt at a solution I want to calculate the mean of the data set for use in the Poisson Distribution function. How do I best estimate this. Do I take the arithmetic average of the data set or do I fit to a Poissonian? Which is the better estimator for the true mean?