For a Poisson distribution X∼Poisson(λ)X \sim \text{Poisson}(\lambda)X∼Poisson(λ), what is the Fisher Information I(λ)I(\lambda)I(λ)?
λ\lambdaλ
1/λ1/\lambda1/λ
λ2\lambda^2λ2
1/λ21/\lambda^21/λ2