The problem as stated is Let X have a poisson distribution w/ lambda = n.

If Y= (X-n)/Sqrt(n), find the MGF for Y.

I know that M(t) for X is given by e^n((e^t)-1). I cannot figure out how to make the jump to find the MGF for Y. I have tried finding the expected value of e^ty but what I get makes no sense. Help.....