ex·pect·ed value (?k-sp?k?t?d)n.1. A quantity expressing a typical or average value of a random variable.2. The sum (for discrete variables) or integral (for continuous variables) of the product of a random variable with its probability density function, over its range of values.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.expected value n (Statistics) 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. Also called: mathematical expectation Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014