\[ \operatorname{E}(X) = \int^b_a x f(x) \> dx \]
- \[ \operatorname{sd}(X) = \sqrt{\operatorname{Var}(X)} = \sqrt{\oepratorname{E}(X^2)-[\operatorname{E}(X)]^2} \]
+ \[ \operatorname{sd}(X) = \sqrt{\operatorname{Var}(X)} = \sqrt{\operatorname{E}(X^2)-[\operatorname{E}(X)]^2} \]
\end{document}