Question

What is the variance of a geometric distribution for a given pobability?

Answer 1

variance `=(1-p)/p^2`

Explanation:

For example, a geometric with p=0.4 ...

mean `=1/p=1/0.4=2.5`

variance `=(1-p)/p^2=(1-0.4)/0.4^2=0.6/0.16=3.75`

s.d. `=sqrt(3.75)~~1.9365`

hope that helped