Question

poisoon variable f (2)=3 f (4) what is the variance of x

Answer 1

Answer:

Poisson's distribution implies

P(X=n)=

n!

λ

n

e

−λ

Where mean=variance=λ

Hence P(x=2)=3P(x=3)

3 3!

λ 3

e −λ

= 2!λ

2 e −λ

3λ=3

λ=1

Hence mean=variance=1