expected value

American  

noun

1. Statistics, Mathematics. mathematical expectation.

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expected value British  

noun

1. Also called: mathematical expectation.  statistics the sum or integral of all possible values of a random variable, or any given function of it, multiplied by the respective probabilities of the values of the variable. Symbol: E ( X ). E ( X ) is the mean of the distribution; E ( X–c ) = E ( X )– c where c is a constant

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Etymology

Origin of expected value

First recorded in 1945–50

Example Sentences

You find out today whether you’ve “won,” and that instant verdict hits harder than any lesson in expected value.

From The Wall Street Journal • Dec. 2, 2025

But for Dyne, Matteis believes the deal for Avidity is “highly validating,” as it corroborates the expected value of muscle-delivery technology and the attractiveness of the markets for even rare diseases like DMD.

From MarketWatch • Oct. 27, 2025

He said customers wanted to see investment and improvements to services, but also expected "value for money and to be treated fairly".

From BBC • Feb. 14, 2025

"But quantum physics says that there are always certain fluctuations. The fluctuations, i.e. the deviations from the expected value, are closely related to the temperature."

From Science Daily • Mar. 27, 2024

The expected value of a quantity is simply the average of its values weighted according to their probabilities.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos