diff --git a/book/book.tex b/book/book.tex
index 7465269e..4f73ca95 100644
--- a/book/book.tex
+++ b/book/book.tex
@@ -1649,7 +1649,7 @@ \section{Probability of connectivity}
 def prob_connected(n, p, iters=100):
     tf = [is_connected(make_random_graph(n, p))
           for i in range(iters)]
-    return np.mean(bool)
+    return np.mean(tf)
 \end{code}
 
 The parameters \py{n} and \py{p} are passed along to \py{make_random_graph};
@@ -2135,7 +2135,7 @@ \section{WS graphs}
 consider the edges in a particular order and rewire each one with
 probability $p$.  If an edge is rewired, they leave the first node
 unchanged and choose the second node at random.  They don't allow self
-loops or multiple edges; that is, you can't have a edge from a node to
+loops or multiple edges; that is, you can't have an edge from a node to
 itself, and you can't have more than one edge between the same two
 nodes.