How do you determine the variance of a Poisson distribution?
1 Answer
Nov 8, 2015
The Poisson Distribution is that of a discrete random variable. Hence we use the summation procedure.
Explanation:
For any random variable X, the variance is defined as
sigma^2 = E(X^2 ) -[E(X)]^2 .
if the random variable is a discrete random variable, we obtain
sigma^2 =sum_0^infty x^2 p(x) -[ sum_0^inftyx.p(x)]^2 where
p(x) =((e^(-mu}mu^x) / (x!)) x = 0,1,2,3,-----infty
Finally, the answer is obtained asmu .