### Calculating expected value

Expected Value for a Discrete Random Variable. E(X)=\sum x_i p_i. x_i= value of the i th outcome p_i = probability of the i th outcome. According to this formula. Definition of expected value & calculating by hand and in Excel. Includes video. Find an expected value for a discrete random variable. Identify all possible outcomes. Calculating the expected value (EV) of a variety of possibilities is a statistical tool for determining the most likely result over time. This article is about the term used in probability theory and statistics. What is Expected Value? Basically, all the formula is telling you to do is find the mean by adding the probabilities. In this example, we see that, in the long run, we will average a total of 1. Since your list of outcomes should represent all the possibilities, the sum of probabilities should equal 1. So your values for X are 0,1,2 and 3. Expected Value Discrete Random Variable given a formula, f x. Turning Data Into Information Lesson 3: The expected profit from such a bet will be. The expected value of this scenario is:. I too agree, sometimes the biggest challenge is to know where to plug in the numbers in the equation. You toss a coin until a tail comes up. Probability and Statistics In other languages:

### Calculating expected value Video

Expected Value Formula However, recognize that there are four different suits, and there are, for example, multiple ways to draw a value of It uses estimated probabilities with multivariate models , to examine possible outcomes for a proposed investment. You should either list these or create a table to help define the results. The probability of the outcomes usually depends on many external factors. You toss a fair coin three times. The more problems I practice, the more it seems to click, though. The expected value of this scenario is: In this sense this book can be seen as the first successful attempt of laying down the foundations of the theory of probability. Lose your entire investment. However, they did not publish their findings. The expected value is a key aspect of how one characterizes a probability distribution ; it is one type of location parameter. Expected values can also be used to compute the variance , by means of the computational formula for the variance.

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