Question: 2015 Fall Final - 23
Let $S$ be a uniformly random 2-element subset of $\{1,2,3,4\}$, and let $X$ be the number of
elements of $S$ that are even. What is the expected value $\mathbb{E}(X)$ of $X$?
(a)
1
(b)
3/2
(c)
2
(d)
5/2