381 bytes added
, 13:09, July 3, 2008
The '''expectation''' of random variable <math>X</math> with probability density function
<math>f(x)</math> is
:<math>
\mbox{E}[X]
=\int\limits_{-\infty}^\infty
x
f(x)dx.
</math>
This is also the [[mean]] of random variable <math>X</math>.
The expectation with respect to some function <math>g(X)</math> is
:<math>
\mbox{E}[g(X)]
=\int\limits_{-\infty}^\infty
g(x)
f(x)dx.
</math>