# Homework Help: Finding the marginal distribution of a random variable w/ a random variable parameter

1. Jan 25, 2010

### ryzeg

STAT134/150: Marginal distr. of a random var. w/ random var. param., given distrs

Hello,

I am a little shaky on my probability, so bear with me if this is a dumb question...

Anyway, the distributions of the two random variables are given:

$$X : Poisson (\lambda$$)
$$\lambda : Exp. (\theta)$$

I simply need the marginal distribution of X and the conditional density for $$\lambda$$ given a value for X

I have all the equations for dependent distributions, but do not know how to apply them to this ostensibly easy problem...

Any help?

Last edited: Jan 25, 2010