# What are the mean and standard deviation of a probability density function given by #Pr(X=k) = (80^ke^-80)/(k!) # for #k in {0,1,2... oo}#?

##### 1 Answer

Oct 17, 2016

#### Explanation:

is a Poisson distribution, the standard formula being:

the mean and variance are given by

the proof of these results can be found from a search on the web.

the sd is the square root of the variance hence the results