P(E intersect F ) = number of strings starting with 1 and with an odd number of 1 / number of strings of lenght 3
P(E) = 4 / 8 = 1 / 2 ( 1 0 0 ; 0 1 0 ; 0 0 1 ; 1 1 1 )
P(F) = 1 / 2
And by using the theorem of independence, we find that E and F are independent. --rtabchou