[Taniahobbit]

I need help with these two 2nd year university statistics problem:

Q.1 Let the discrete random variable of Y have a conditional uniform probability distribution on {1,2,. x}; ie:
P(Y=y|X=x)=1/x, y=1,2,. x.
Determine the unconditional mean and variance of Y in terms of the mean and variance of the conditioning random variable X.

Q.2 Let the random variable Y have a conditional Poisson distribution, for x>0:
P(Y=y|X=x)=x^ye^(-x)/y!; y=0,1,2,. infinity
so that the conditional mean E(Y|X=x) and conditional variance Var (Y|X=x) are both equal to x. If X is equal to z1 with probability 1-p or z2 with probability p, determine the unconditional mean and variance of Y, and the actual probability distribution of Y.

Thanks,
Tania

[Clough]

How do you need help with the problems? What do you think the answers should be? And, how did you arrive at the answers? Please see the following link.

https://www.askmehelpdesk.com/math-s...board-b-u.html

[Taniahobbit]

I just don't know how to start these questions. How do I find the mean and variance?