Two fair dice are thrown, with the scores (X1, X2).

[CherubDown]

Need help with this problem, please!

Two standard, fair dice are thrown, and the scores (X1, X2) are recorded. Find the expected value of each of the following variables:
(a) Y = X1 + X2
(b) Z = X1*X2

I don't even understand what it's asking! :( Any help is appreciated.

 

[mathman]

Expected value means average. For one die, it is 3.5. For the sum, the averages just add, so E(Y)=7. For the product you need to assume the dice are independent - in which case E(Z)=12.25 (the product).

 

[Cant or Wont]

Not sure just providing the correct answer will be enough here. When you say you "don't even understand what it's asking" how much do you know? If I were to ask you the expected value of a single dice roll would you know how to arrive at the answer to such a question?