Bump to v4.0.0.

mean.js

@@ -0,0 +1,20 @@
+import sum from './sum';
+
+/**
+ * Computes the mean of the values in `array`.
+ *
+ * @static
+ * @memberOf _
+ * @category Math
+ * @param {Array} array The array to iterate over.
+ * @returns {number} Returns the mean.
+ * @example
+ *
+ * _.mean([4, 2, 8, 6]);
+ * // => 5
+ */
+function mean(array) {
+  return sum(array) / (array ? array.length : 0);
+}
+
+export default mean;