mathematics - Word For the Process of Finding Return on Investment

I am told that if I invest $20 in this Apple Stock, in one years time there is a:

• 10% chance I'll get back $25


• 10% chance I'll get back $20


• 30% chance I'll get back $15


• 50% chance I'll get back $10

So my what I'm calling my "Return on Investment" would be: $25 * .1 + $20 * .1 + $15 * .3 + $10 * .5 = $14

I'm assuming this is some sort of statistical calculation that I just did, but I'd like to know the name of this statistical process. (I would say something like amortization, but that's not right.)