What does the term "expected value" mean?

Question

4531 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-04-15T15:48:41

see below

For real life data the mean of the frequency distribution is calculated by the formula

$¯ x = \frac{\sum f x}{n}$ $barx=(sumfx)/n$

for a probability distribution the expected value is the corresponding calculation; the theoretical mean if you like.

For discrete distributions

$μ = E (X) = \sum x P (X = x)$ $mu=E(X)=sumxP(X=x)$

for continuous distribution

$μ = E (X) = \int_{a l l x} x f (x) d x$ $mu=E(X)=int_(allx)xf(x)dx$

in both cases since the total probability is $1$ $1$ we do not need to divide by anything.