# Expected Value

The expected value of a discrete random variable is the sum of the product of the probability of each event by the value of that event.

The **expected value **of a random variable, X, is denoted by **µ** or** E(X)**.

#### Variance of a Discrete Random Variable

#### Standard Deviation of a Discrete Random Variable

#### Example

Calculate the expected value, variance, and standard deviation of the probability distribution for the possible outcomes that can be obtained by throwing a die.

x | p _{i} |
x · p _{i} |
x^{ 2 }· p_{i} |
---|---|---|---|

1 | |||

2 | |||

3 | |||

4 | |||

5 | |||

6 | 1 | 6 | |

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