\[ \Pr(X \ge a) = 1 - \Pr(X < a) \]
+ \subsection{Expected value of a binomial distribution}
+
+ \[ E(X \sim \operatorname{Bi}(n,p))=np \]
+
+ \subsection{Variance}
+
+ \[ \sigma^2(X) = np(1-p) \]
+
+ \subsection{Standard deviation}
+
+ \[ \sigma(X) = \sqrt{np(1-p)} \]
+
\end{document}