1. The problem statement, all variables and given/known data I'm given list x, with 8 elements. List y, with 10 elements. Find expectation and variance of x,y,x+y,xy 2. Relevant equations 3. The attempt at a solution E(x), E(y), E(x+y), var(x),var(y) are all straightforward. But how do I find E(xy)? Do I just have to multiply out everything? Then I would need to find mean and variance of a sample set of 80. Is there an easier way? I am given literally no information about the numbers. Not what they represent, if they're related, nothing.