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

Baron said he thinks SpaceX valuation is heading much higher from the expected value of close to $2 trillion at the IPO.

From Barron's • Jun. 8, 2026

"For me, making an accurate measurement is a way of bringing order to the universe, whether or not the number agrees with the expected value," he added.

From Science Daily • May 18, 2026

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

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