From 5443a3ebc4ec40f8633590e81fdee92406a788e0 Mon Sep 17 00:00:00 2001
From: andyeisenberg <andyjeisenberg@gmail.com>
Date: Sat, 1 Aug 2026 18:43:12 +0000
Subject: [PATCH] Added an exercise answer

---
 source/sec-Variance.ptx | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/source/sec-Variance.ptx b/source/sec-Variance.ptx
index 2ddd5e1..929c8f9 100644
--- a/source/sec-Variance.ptx
+++ b/source/sec-Variance.ptx
@@ -264,9 +264,17 @@
       <statement>
         <p>
           Suppose we flip a coin <m>n = 100</m> times, and let <m>N</m> count the number of heads.
-          If the coin comes up heads on a flip with probability <m>p = 0.4</m>, what is <m>\Var(N)</m>? What if <m>n = 80</m> and <m>p = 0.6</m>? What if <m>n = 200</m> and <m>p = 0.5</m>?
+          If the coin comes up heads on a flip with probability <m>p = 0.3</m>, what is <m>\Var(N)</m>? What if <m>n = 80</m> and <m>p = 0.6</m>? What if <m>n = 200</m> and <m>p = 0.5</m>?
         </p>
       </statement>
+
+      <answer>
+        <p>
+          When <m>n = 100</m> and <m>p = 0.3</m>, <m>\Var(N) = 21</m>.
+          When <m>n = 80</m> and <m>p = 0.6</m>, <m>\Var(N) = 19.2</m>.
+          When <m>n = 200</m> and <m>p = 0.5</m>, <m>\Var(N) = 50</m>.
+        </p>
+      </answer>
     </exercise>
 
     <exercise>