diff --git a/likelihood/lecture/mlemean.py b/likelihood/lecture/mlemean.py
index f0b6506..5fd4932 100644
--- a/likelihood/lecture/mlemean.py
+++ b/likelihood/lecture/mlemean.py
@@ -41,7 +41,7 @@ for mu in mus :
         ax.text(mu-0.1, 0.04, '?', zorder=1, ha='right')
     else :
         ax.text(mu+0.1, 0.04, '?', zorder=1)
-for k in np.arange(len(mus)) :
+for k in range(len(mus)) :
     ax.plot(x, g[:,k], zorder=5)
 ax.scatter(xd, 0.05*rng.rand(len(xd))+0.2, s=30, zorder=10)