Expected Value (i.e., Mean) of a Discrete Random Variable. Law of Large To calculate the standard deviation we first must calculate the variance. From the. How to Calculate an Expected Value. Expected value (EV) is a concept employed in statistics to help decide how beneficial or harmful an action might be. Definition of expected value & calculating by hand and in Excel. Includes video. Find an expected value for a discrete random variable. Back to Top Find an Expected Value in Excel Step 1: He began to discuss the problem in a now famous series of letters to Pierre de Fermat. One example sequence of ten rolls of the die is 2, 3, 1, 2, 5, 6, 2, 2, 2, 6, which has the average of 3. We now turn to a continuous random variable, which we will denote by X. Computing Computer programming Computer science Hour of Code Computer animation. Add up the values from Step 1: If you prefer an online interactive environment to learn R and statistics, this free R Tutorial by Datacamp is a great way to get started. In a situation like the stock market, professional analysts spend their entire careers trying to determine the likelihood that any given stock will go up or down on any given day. Comparing Two Groups Lesson This version of the formula is helpful to see because it also works when we have an infinite sample space. To use this calculator, a user simply enters in the value of each event or x and the probability of each event or x occurring. Given this information, the calculation is straightforward:.