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 · pi |
|---|---|---|---|
| 1 |  |
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| 2 | |
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| 3 | |
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| 4 | |
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| 5 | |
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| 6 | |
1 | 6 |
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