diff --git a/variance_hydrogen.py b/variance_hydrogen.py
index 0892f79..e628595 100644
--- a/variance_hydrogen.py
+++ b/variance_hydrogen.py
@@ -36,5 +36,5 @@ for a in [0.1, 0.2, 0.5, 0.9, 1., 1.5, 2.]:
     E  = E  / norm
     E2 = E2 / norm
 
-    s2 = E2 #- E**2
+    s2 = E2 - E**2
     print(f"a = {a} \t E = {E:10.8f} \t \sigma^2 = {s2:10.8f}")