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Expected Value

Expected Value
Mean of a Random Variable

A quantity equal to the average result of an experiment after a large number of trials. For example, if a fair 6-sided die is rolled, the expected value of the number rolled is 3.5. This is a correct interpretation even though it is impossible to roll a 3.5 on a 6-sided die. This sort of thing often occurs with expected values.

 

Two tables showing Expected Value formula: E=P1x1+P2x2+…+Pnxn, with die example yielding 3.5.

 

See also

Weighted average