# Question: let 0 1 3 that is all...

###### Question details

Let Ω = {0, 1} 3 , that is, all possible (ordered) triples of zeros and ones. Suppose that all outcomes have equal probability. We define three random variables X1, X2, and X3 on this space representing the first, second, and third digit, respectively. We also define X = X1 + X2 + X3.

compute: E(E(X|X1)|X2)