**Random Variable**

A **random variable **is a function that assigns a real number to each outcome of an experiment.

**Expected Value**

Suppose the random variable x can take on the n values x_{1},x_{2},x_{3},……..x_{n}.

Also, suppose the probabilities that values occur are, respectively,

P_{1}.P_{2},……….P_{n}. Then the expected value of the random variable is

E(x) = x_{1} p_{1 }+ x_{2}p_{2}+……..x_{n}p_{n.}