1.1.3.2 Expected values of discrete random variable
The expected value of a discrete random variable is the weighted average of all its possible values, taking the probability of each outcome as its weight. It can be calculated by multiplying each possible value of the random variable by its probability and adding. In mathematical terms, if X denotes the random variable, its expected value is denoted by E(X). Let us suppose that X can take nparticular values of
,
,...,
and that the probability of
is Then,
1
( )
...[1.01]
n
i
i
n
n
i
i
i
E X
x p
x p
x p
Table 1.0 shows an example of expected value of variable X with two dice.
Table 1.0:Expected value of variable X with two dice
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