For a Poisson distribution X, suppose I know the variance of X is 5. (1) By property of Poisson, what is mean of X. (2) Compute P(X≥3) (3) Does Poisson have the property of lack of memory? List at...

For a Poisson distribution X, suppose I know the variance of X is 5.
(1) By property of Poisson, what is mean of X.
(2) Compute P(X≥3)
(3) Does Poisson have the property of lack of memory? List at least one name of distribution with such property.

please explain full with all the steps