... VARIANCE 22 1Answer. Go back to throwing a coin twice independently and define A = {HH, HT }; B ={T H, HH}, and C = {HH, T T }, and x1= IA, x 2 = IB, and y = IC. They are pairwise indepen-dent, ... E[y] 2 (E[x 2 ] − E[x] 2 ) + (E[x 2 ] − E[x] 2 )(E[y 2 ] − E[y] 2 ) = E[x 2 ] E[y 2 ] −E[x] 2 E[y] 2 = E[(xy) 2 ] − E[xy] 2 . 8.6. Conditional Expectation and VarianceThe conditional expectation ... np1− p 2 1−p1p 2 ··· −p1pr−p 2 p1p 2 − p 2 2··· −p 2 pr............−prp1−prp 2 ··· pr− p 2 r.7 .2. THE PROBABILITY LIMIT AND THE LAW OF LARGE...