Enter the probability of an event occurring and the number of trials into the calculator to determine the expected value.

Expected Value Formula

The following formula is used to calculate an expected value.

EV = P(x) * n

  • Where EV is the expected value of the expected number of successes
  • P(x) is the probability of event x occurring
  • n is the number of trials

Expected Value Definition

An expected value is the sum of the probability of an event occurring and the number of trials performed.


Expected Value Example

How to calculate an expected value?

  1. First, determine the probability of the event happening.

    This will be the probability of a given value, or the probability or a given even. For this example we will say there is a 25% chance of an event occurring.

  2. Next, determine the number of trials.

    For this example we will say there will be 100 trials.

  3. Finally, calculate the expected value.

    Calculate the expected number of events given the 25% chance and the 100 trials, so 100*.25 = 25 total expected.

FAQ

What is an expected value?

An expected value is the total expected value given a certain probability of a value occurring and a certain number of trials.