COMPMID-378 NEMeanStdDev test completed.

Change-Id: I46fb77c0cb507a4c0fe3264a89dd7b2ba63c44dc
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/77427
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Steven Niu <steven.niu@arm.com>
diff --git a/tests/validation/ReferenceCPP.h b/tests/validation/ReferenceCPP.h
index be5a733..4173b8b 100644
--- a/tests/validation/ReferenceCPP.h
+++ b/tests/validation/ReferenceCPP.h
@@ -42,6 +42,13 @@
 class ReferenceCPP final : public Reference
 {
 public:
+    /** Function to compute the mean and standard deviation of a tensor.
+     *
+     * @param[in]  src     Input tensor.
+     * @param[out] mean    Mean of the tensor.
+     * @param[out] std_dev Standard deviation of the tensor
+     */
+    static void mean_and_standard_deviation(const RawTensor &src, float &mean, float &std_dev);
     /** Function to compute the integral image of a tensor.
      *
      * @param[in]  src Input tensor.