A quick introduction to expected value formulas. Expected Value Formula. Stephanie Glen. Loading. The weighted average formula for expected value is given by multiplying each possible value for the random variable by the probability that the random variable. 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.
It is known as a weighted average because it takes into account the probability of each outcome and weighs it accordingly. The requirement that is called absolute integrability and ensures that the improper integral is well-defined. By contrast, the variance is a measure of dispersion of the possible values of the random variable around the expected value. The probability P of getting a question right if you guess: Law of Large Numbers: So your values for X are 0,1,2 and 3. You would need to be provided with some additional information before you could calculate the probabilities in these examples.
Expected value formula Video