Definition of expected value & calculating by hand and in Excel. Includes video. Find an expected value for a discrete random variable. Definition of expected value, from the Stat Trek dictionary of statistical terms and concepts. This statistics glossary includes definitions of all technical terms used. we shall discuss two such descriptive quantities: the expected value and the . In statistics, one is frequently concerned with the average value of a set of data. These calculations will look like this: Expected value is exactly what you might think it means intuitively: Basic Expected Value Example To calculate the EV for a single discreet random variable, you must multiply the value of the variable by the probability of that value occurring. Because the probabilities that we are working with here are computed using the population, they are symbolized using lower case Greek letters. I too agree, sometimes the biggest challenge is to know where to plug in the numbers in the equation. Search Statistics How To Statistics for the rest of us! You may need to use a sample space The sample space for this problem is: But finally I have found that my answers in many cases do not differ from theirs. Er ergibt sich zum Beispiel bei unbegrenzter Wiederholung des zugrunde liegenden Experiments als Durchschnitt der Ergebnisse. Pascal, being a mathematician, was provoked and determined to solve the problem once and for all. To empirically estimate the expected value of a random variable, one repeatedly measures observations of the variable and computes the arithmetic mean of the results. Expected values can also be used to compute the variance , by means of the computational formula for the variance. Basic Expected Value Example To calculate the EV for a single discreet random variable, you must multiply the value of the variable by the probability of that value occurring.