diff --git a/src/TowseyLibrary/NormalDist.cs b/src/TowseyLibrary/NormalDist.cs
index add6452f0..7989842ac 100644
--- a/src/TowseyLibrary/NormalDist.cs
+++ b/src/TowseyLibrary/NormalDist.cs
@@ -213,7 +213,7 @@ public static void AverageAndVariance(double[] data, out double av, out double v
                 variance /= N;
             }
             else
-                if (N > 2)
+                if (N > 1)
             {
                 variance /= N - 1;
             }