# Probability and expected value

In probability and statistics, the expectation or expected value, is the weighted average value of a random variable. The math behind this kind of expected value is: The probability (P) of getting a question right if you guess The number of questions on the. 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. Using representations as Riemann—Stieltjes integral and integration by parts the formula can be restated as. The esc wieviele teilnehmer P of getting a question right if you guess: If we wanted to know the probability of flipping a coin twice and heads coming up at least once, we would apply this formula: This is because, when the first i tosses yield tails, the number of tosses is at least i. Adding 3 and 4 gives us the expected value: So if we were gambling, how should we look at the outcome? X is the number of heads which appear.

### Probability and expected value Video

Prob & Stats - Random Variable & Prob Distribution (25 of 53) Expected Value - Example 1 Example What is the expected value when we roll a fair die? Because of the law of large numbers , the average value of the variable converges to the EV as the number of repetitions approaches infinity. Congrats on Buzzam Radio. Standard Deviation for a Discrete Random Variable. Der Erwartungswert selten und doppeldeutig Mittelwert ist ein Grundbegriff der Stochastik. Views Read Edit View history. A fair six-sided die is tossed. The expected value of an uncertain event is the sum of the possible payoffs multiplied by each payoff's chance of occurring. Working With Discrete Random Variables This video walks through one example of a discrete random variable. Dies folgt daraus, dass der Erwartungswert das erste Moment ist und die k-ten Ableitungen der momenterzeugenden Funktion an der 0 genau die k-ten Momente sind. One-Way Analysis of Variance ANOVA Lesson Add up the values from Step 1: Wahrscheinlichkeiten von Ereignissen lassen sich auch über den Erwartungswert ausdrücken. You toss a coin until a tail comes up. This page was last edited on 3 July , at GCSE MATHS A-LEVEL MATHS GCSE to A-Level Pure Maths Statistics Mechanics A-Level Maths Past Papers Other A-Level Subjects REVISION TIMETABLE Revision Science REVISION WORLD Revision Videos. In this case, the values are headed towards 2, so that is your EV. The expectation of X may be computed by.