question_answer 1)

In a meeting, 70% of the members favour and 30% oppose a certain proposal. A member is selected at random and we take X = 0 if he opposed, and X = 1 if he is in favour. Find E(X) and Var (X). 

Answer:

Here X = 0, 1       and P(X = 0) =       P(X = 1) = 70%       Probability distribution             E(X) =              E (X) = 0.7       and Var(X) = E (X2) ? [E(X)]2       = 0.7 ? (0.7)2       = 0.70 ? 0.49 = 0.21.