diff --git a/variance.py b/variance.py
new file mode 100644
index 0000000..9954066
--- /dev/null
+++ b/variance.py
@@ -0,0 +1,41 @@
+from algorithm import algorithm
+import json
+import ray
+
+@ray.remote
+class average(algorithm):
+    def __init__(self):
+        self.config_dict_ = None
+        self.config_ = None
+        self.average_number_ = 10
+        self.present_number_ = 0
+        self.window_1_ = []
+        self.sum = 0
+        self.average = 0
+
+
+    def set_config(self, config):
+        self.config_ = config
+        self.config_dict_ = json.loads(self.config_)
+        self.average_number_ = self.config_dict_["AVERAGE_NUMBER"]
+
+    def config(self):
+        return self.config_
+
+    def eval(self, value):
+        self.present_number_ = len(self.window_1_)
+        if self.present_number_ < self.average_number_:
+            self.window_1_.append(value)
+            self.sum = 0
+            for i in self.window_1_:
+                self.sum = self.sum + i
+            self.average = self.sum / len(self.window_1_)
+            return self.average
+        else:
+            self.sum = 0
+            del self.window_1_[0]
+            self.window_1_.append(value)
+            for i in self.window_1_:
+                self.sum = self.sum + i
+            self.average = self.sum / len(self.window_1_)
+            return self.average