From: Andrew Lorimer <andrew@lorimer.id.au>
Date: Sat, 10 Aug 2019 04:58:51 +0000 (+1000)
Subject: [methods] E(X), Var(X) and sd(X) for bin. dists
X-Git-Tag: yr12~69
X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/328a7e04074c85541b85953aba6034694418d114?ds=sidebyside

[methods] E(X), Var(X) and sd(X) for bin. dists
---

diff --git a/methods/statistics.tex b/methods/statistics.tex
index d776b4a..4c398f0 100644
--- a/methods/statistics.tex
+++ b/methods/statistics.tex
@@ -154,4 +154,16 @@
 
   \[ \Pr(X \ge a) = 1 - \Pr(X < a) \]
 
+  \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}