diff --git a/lib/neuralnetwork.js b/lib/neuralnetwork.js
index cbbb39c..98a9120 100644
--- a/lib/neuralnetwork.js
+++ b/lib/neuralnetwork.js
@@ -70,7 +70,7 @@ NeuralNetwork.prototype = {
         var err = this.trainItem(data[j].input, data[j].output);
         sum += Math.pow(err, 2);
       }
-      error = Math.sqrt(sum) / data.length; // mean squared error
+      error = Math.sqrt(sum / data.length); // mean squared error
 
       if(callback && (i % resolution == 0))
         callback({error: error, iterations: i});
@@ -178,7 +178,7 @@ Layer.prototype = {
     var sum = this.reduce(function(sum, node) {
       return sum + Math.pow(node.error, 2);
     }, 0);
-    return Math.sqrt(sum) / this.getSize(); // mean squared error
+    return Math.sqrt(sum / this.getSize()) // mean squared error
   },
 
   getSize : function() {