diff --git a/source/_integrations/statistics.markdown b/source/_integrations/statistics.markdown
index 89cba600eff..346b8b1c314 100644
--- a/source/_integrations/statistics.markdown
+++ b/source/_integrations/statistics.markdown
@@ -155,3 +155,7 @@ unique_id:
   required: false
   type: string
 {% endconfiguration %}
+
+### An important note on `max_age` and `sampling_size`
+
+The `max_age` option is only valid within the measured samples specified by `sampling_size` (default 20). Specify a wide-enough `sampling_size` if using an extended max-age (e.g., when looking for `max_age` 1 hour, a sensor that produces one measurement a minute should have at least a `sampling_size` of 60.