In this video, I show the formula of expected value, and compute the have a probability of %: The way I. In probability theory, the expected value of a random variable, intuitively, is the long-run .. This is because an expected value calculation must not depend on the order in which the possible outcomes are presented, whereas in a conditionally. This Expected Value calculator calculates the expected value, or the mean in advance, of a number set or group of numbers. Printer-friendly version Expected Value i. If this series does not converge absolutely, we say that the expected value of X does not exist. If one considers the joint probability density function of X and Y , say j x , y , then the expectation of XY is. For example, suppose we toss a coin where the probability of heads is p. Conceptually, the variance of a discrete random variable is the sum of the difference between each value and the mean times the probility of obtaining that value, as seen in the conceptual formulas below:. According to the model, one can conclude that the amount a firm spends to protect information should generally be only a small fraction of the expected loss i. To calculate the standard deviation we first must calculate the variance. X n having a joint density f: In some cases, you may be able to assign a specific dollar value to the possible outcomes. Computing Computer programming Computer science Hour of Code Computer animation. What is the expected number of points Marvin will score? Updated May 07, In this example, we see that, in the long run, we will average a total of 1. If a random variable X is always less than or equal to another random variable Y , the expectation of X is less than or equal to that of Y:.