Let X and Y be independant poisson processes. If X+Y=n, find E[(X-Y)^2/X+Y]

i have subsituted in X-Y=n-2Y and X+Y=n this gives me the following:

E[n^2/n]-4E[nY/n]+4E[Y^2/n] which i am not sure how to simplify

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- Mar 21st 2011, 09:41 PMulysses123Probability
Let X and Y be independant poisson processes. If X+Y=n, find E[(X-Y)^2/X+Y]

i have subsituted in X-Y=n-2Y and X+Y=n this gives me the following:

E[n^2/n]-4E[nY/n]+4E[Y^2/n] which i am not sure how to simplify - Mar 21st 2011, 10:43 PMmatheagle
we need to know the parameter involved with these Poissons

and you need to do more than plug in n, for X+Y. - Mar 21st 2011, 11:16 PMulysses123
the parameters are a for X and b for Y, they have no specified values.

How can i go about solving this?