diff --git a/03_classification.ipynb b/03_classification.ipynb
index 235b680..9812293 100644
--- a/03_classification.ipynb
+++ b/03_classification.ipynb
@@ -1744,8 +1744,8 @@
    "source": [
     "from sklearn.model_selection import cross_val_score\n",
     "\n",
-    "scores = cross_val_score(svm_clf, X_train, y_train, cv=10)\n",
-    "scores.mean()"
+    "svm_scores = cross_val_score(svm_clf, X_train, y_train, cv=10)\n",
+    "svm_scores.mean()"
    ]
   },
   {
@@ -1771,8 +1771,8 @@
     "from sklearn.ensemble import RandomForestClassifier\n",
     "\n",
     "forest_clf = RandomForestClassifier(random_state=42)\n",
-    "scores = cross_val_score(forest_clf, X_train, y_train, cv=10)\n",
-    "scores.mean()"
+    "forest_scores = cross_val_score(forest_clf, X_train, y_train, cv=10)\n",
+    "forest_scores.mean()"
    ]
   },
   {
@@ -1782,6 +1782,27 @@
     "That's much better!"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Instead of just looking at the mean accuracy across the 10 cross-validation folds, let's plot all 10 scores for each model, along with a box plot highlighting the lower and upper quartiles, and \"whiskers\" showing the extent of the scores (thanks to Nevin Yilmaz for suggesting this visualization). Note that the `boxplot()` function detects outliers (called \"fliers\") and does not include them within the whiskers. Specifically, if the lower quartile is $Q_1$ and the upper quartile is $Q_3$, then the interquartile range $IQR = Q_3 - Q_1$ (this is the box's height), and any score lower than $Q_1 - 1.5 \\times IQR$ is a flier, and so is any score greater than $Q3 + 1.5 \\times IQR$."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 124,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "plt.figure(figsize=(8, 4))\n",
+    "plt.plot([1]*10, svm_scores, \".\")\n",
+    "plt.plot([2]*10, forest_scores, \".\")\n",
+    "plt.boxplot([svm_scores, forest_scores], labels=(\"SVM\",\"Random Forest\"))\n",
+    "plt.ylabel(\"Accuracy\", fontsize=14)\n",
+    "plt.show()"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1796,7 +1817,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 124,
+   "execution_count": 125,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1806,7 +1827,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 125,
+   "execution_count": 126,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1830,7 +1851,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 126,
+   "execution_count": 127,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1857,7 +1878,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 127,
+   "execution_count": 128,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1873,7 +1894,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 128,
+   "execution_count": 129,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1885,7 +1906,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 129,
+   "execution_count": 130,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1894,7 +1915,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 130,
+   "execution_count": 131,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1910,7 +1931,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 131,
+   "execution_count": 132,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1925,7 +1946,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 132,
+   "execution_count": 133,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1942,7 +1963,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 133,
+   "execution_count": 134,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1951,7 +1972,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 134,
+   "execution_count": 135,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1967,7 +1988,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 135,
+   "execution_count": 136,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -1986,7 +2007,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 136,
+   "execution_count": 137,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2002,7 +2023,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 137,
+   "execution_count": 138,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2011,7 +2032,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 138,
+   "execution_count": 139,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2034,7 +2055,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 139,
+   "execution_count": 140,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2051,7 +2072,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 140,
+   "execution_count": 141,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2067,7 +2088,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 141,
+   "execution_count": 142,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2089,7 +2110,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 142,
+   "execution_count": 143,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2113,7 +2134,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 143,
+   "execution_count": 144,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2132,7 +2153,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 144,
+   "execution_count": 145,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2148,7 +2169,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 145,
+   "execution_count": 146,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2172,7 +2193,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 146,
+   "execution_count": 147,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2190,7 +2211,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 147,
+   "execution_count": 148,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2216,7 +2237,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 148,
+   "execution_count": 149,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2239,7 +2260,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 149,
+   "execution_count": 150,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2291,7 +2312,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 150,
+   "execution_count": 151,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2316,7 +2337,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 151,
+   "execution_count": 152,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2348,7 +2369,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 152,
+   "execution_count": 153,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2359,7 +2380,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 153,
+   "execution_count": 154,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2375,7 +2396,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 154,
+   "execution_count": 155,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2391,7 +2412,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 155,
+   "execution_count": 156,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2407,7 +2428,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 156,
+   "execution_count": 157,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -2430,7 +2451,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 157,
+   "execution_count": 158,
    "metadata": {},
    "outputs": [],
    "source": [