In the below attached file there is a question in which they asked to find pmf of y Solution is also attached below: I didn't understand how p(y) = (e^(-λ)*(λp^y)/y!)* summation(x-y)!
There's a misprint. It should read: \(\frac{e^{-y}(\lambda p)^y}{y!} \sum_{x=y}^{\infty} \frac{(\lambda (1-p))^{x-y}}{(x-y)!}\)
