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. Then, E(X) is :

$\frac{7}{10}$

F → favour

$\vec{F}$ = oppose

P(F) = 70% = $\frac{7}{10}$

$P(\bar{F}) = 30% = \frac{3}{10}$

So  $E(X) = 0 × \frac{3}{10} + 1 × \frac{7}{10}$

$\frac{7}{10}$