diff --git a/study/001_introduction-to-probability-statistics-and-random-processes/ch2/notes.ipynb b/study/001_introduction-to-probability-statistics-and-random-processes/ch2/notes.ipynb
index f643b71..b7e019d 100644
--- a/study/001_introduction-to-probability-statistics-and-random-processes/ch2/notes.ipynb
+++ b/study/001_introduction-to-probability-statistics-and-random-processes/ch2/notes.ipynb
@@ -53,7 +53,7 @@
     "- **Ordered or unordered**: If ordering matters (i.e.: a1, a2, a3 ≠ a2, a3, a1), this is\n",
     "called ordered sampling. Otherwise, it is called unordered\n",
     "\n",
-    "Counting formula for the type of sampling:\n",
+    "### Counting Formulas\n",
     "\n",
     "- **ordered sampling with replacement:** $n^k$\n",
     "\n",