diff --git a/ch04/README.md b/ch04/README.md
index 37a3dfb6..13be1355 100644
--- a/ch04/README.md
+++ b/ch04/README.md
@@ -1,7 +1,7 @@
 Python Machine Learning - Code Examples
 
 
-##  Chapter 4: Building Good Training Sets – Data Preprocessing
+##  Chapter 4: Building Good Training Datasets – Data Preprocessing
 
 ### Chapter Outline
 
diff --git a/ch04/ch04.ipynb b/ch04/ch04.ipynb
index 325d113d..fdaa9807 100644
--- a/ch04/ch04.ipynb
+++ b/ch04/ch04.ipynb
@@ -22,7 +22,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# Chapter 4 - Building Good Training Sets – Data Preprocessing"
+    "# Chapter 4 - Building Good Training Datasets – Data Preprocessing"
    ]
   },
   {
diff --git a/ch04/ch04.py b/ch04/ch04.py
index d9db4b23..539c3c41 100644
--- a/ch04/ch04.py
+++ b/ch04/ch04.py
@@ -29,7 +29,7 @@
 
 # # Python Machine Learning - Code Examples
 
-# # Chapter 4 - Building Good Training Sets – Data Preprocessing
+# # Chapter 4 - Building Good Training Datasets – Data Preprocessing
 
 # Note that the optional watermark extension is a small IPython notebook plugin that I developed to make the code reproducible. You can just skip the following line(s).