1. The problem statement, all variables and given/known data Fy(y) = 1/2 λ^3 y^2 e^(-λy) Assume E(1/y) = λ/2 Find E(1/y^2) and prove Var(1/y) = λ^2 / 4 2. Relevant equations E(y) = k/λ Var (y) = k/ λ^2 3. The attempt at a solution Hi guys, From the equation given from gamma distribution, I understands clearly that to get Var(y) what I have to do is to square y. i.e. 1/y^2 = (λ/2)^2 = λ^2 / 4. Which is equivalent to E(1/y^2) but I'm no clue on how to set up a proof to show this is correct. I needed help on this, as I have no idea at all on how to proof this.