diff --git a/Chapter1_Introduction/Ch1_Introduction_PyMC3.ipynb b/Chapter1_Introduction/Ch1_Introduction_PyMC3.ipynb
index f5d262c2..be24102a 100644
--- a/Chapter1_Introduction/Ch1_Introduction_PyMC3.ipynb
+++ b/Chapter1_Introduction/Ch1_Introduction_PyMC3.ipynb
@@ -772,7 +772,7 @@
     "ax.set_autoscaley_on(False)\n",
     "\n",
     "plt.hist(lambda_1_samples, histtype='stepfilled', bins=30, alpha=0.85,\n",
-    "         label=\"posterior of $\\lambda_1$\", color=\"#A60628\", normed=True)\n",
+    "         label=\"posterior of $\\lambda_1$\", color=\"#A60628\", density=True)\n",
     "plt.legend(loc=\"upper left\")\n",
     "plt.title(r\"\"\"Posterior distributions of the variables\n",
     "    $\\lambda_1,\\;\\lambda_2,\\;\\tau$\"\"\")\n",
@@ -782,7 +782,7 @@
     "ax = plt.subplot(312)\n",
     "ax.set_autoscaley_on(False)\n",
     "plt.hist(lambda_2_samples, histtype='stepfilled', bins=30, alpha=0.85,\n",
-    "         label=\"posterior of $\\lambda_2$\", color=\"#7A68A6\", normed=True)\n",
+    "         label=\"posterior of $\\lambda_2$\", color=\"#7A68A6\", density=True)\n",
     "plt.legend(loc=\"upper left\")\n",
     "plt.xlim([15, 30])\n",
     "plt.xlabel(\"$\\lambda_2$ value\")\n",