diff --git a/CHANGELOG.md b/CHANGELOG.md
index 415b5ad5..89c070d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Changed
 - `is_imbalanced` parameter added to ConfusionMatrix `__init__` method
 - `statistic_recommend` function modified
+- Document modified
 ## [3.2] - 2021-08-11
 ### Added
 - `classes_filter` function
diff --git a/Document/Document.ipynb b/Document/Document.ipynb
index 2dc1d676..4750b844 100644
--- a/Document/Document.ipynb
+++ b/Document/Document.ipynb
@@ -2127,6 +2127,27 @@
     "<center><p style=\"text-align:center;\">Fig2. Parameter Recommender Block Diagram</p></center>"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "For determining if the dataset is imbalanced, we use the following strategy:"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "$$R=\\frac{Max(P)}{Min(P)}$$"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "$$State=\\begin{cases}Balance & R\\leq 3\\\\Imbalance & R > 3\\end{cases}$$"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": 47,