Mathematical expectation
$$EX = x_1\cdot p_1+x_2\cdot p_2+x3\cdot p3$$
EX - mathematical expectation
x1, x2, x3 ... - posible values of event
p1, p2, p3 ... - probabilities of event
x1, x2, x3 ... - posible values of event
p1, p2, p3 ... - probabilities of event
Find
It is known that:
= 