And of course it's the expected value of this entire thing. Now let's see if we can rewrite this. Well the expected value of the sum of a bunch of random variables is just the sum or difference of their expected values. So this is going to be the same thing. And remember expected value in a lot of context you can view it as just the arithmetic mean. Or in a continuous distribution you can view it as a probability weighted sum or probability weighted integral. Either way, we've seen it before I think.