# Math Help - Expected Value

1. ## Expected Value

What is the expected value of x^2? also written...E(x^2)

I need help with a question that has to do with Time Series Modeling. The class I'm taking in Finance, but I'm hoping some math/science majors in here are familiar with it (I've heard that finance people jacked it from the science people...here's to hoping).

Thanks!

2. Originally Posted by crabchef
What is the expected value of x^2? also written...E(x^2)

I need help with a question that has to do with Time Series Modeling. The class I'm taking in Finance, but I'm hoping some math/science majors in here are familiar with it (I've heard that finance people jacked it from the science people...here's to hoping).

Thanks!
$E(X^2) = \int_{-\infty}^{+\infty} x^2 f(x) \, dx$ where f(x) is the pdf of X.