I'm struggling about a simple task that ask to recover the parameter $\mu$ and $\sigma$ of a lognormal distribution from its expected value $\mathbb{E}${X} and variance Var{X}.
I know that when the sample is relatively large, the sample mean is approximately the population mean $\mu$.
By the way, in this case, all that is given is the expected value which I suppose to be equal to the population mean. Same case for the population variance.
Am I losing some concept behind this?