Fix syntax error and add observed data to assignment model

Author: ghtdak

Chapter3_MCMC/IntroMCMC.ipynb

@@ -466,7 +466,7 @@
       "observations = pm.Normal(\"obs\", center_i, tau_i, value=data, observed=True)\n",
       "\n",
       "# below we create a model class\n",
-      "model = pm.Model([p, assignment, taus, centers])\n"
+      "model = pm.Model([p, assignment, observations, taus, centers])\n"
      ],
      "language": "python",
      "metadata": {},
@@ -529,7 +529,7 @@
       "center_trace = mcmc.trace(\"centers\")[:]\n",
       "\n",
       "# for pretty colors later in the book.\n",
-      "colors = [\"#348ABD\", \"#A60628\"]\n",
+      "colors = [\"#348ABD\", \"#A60628\"] \\\n",
       "if center_trace[-1, 0] > center_trace[-1, 1] \\\n",
       "    else [\"#A60628\", \"#348ABD\"]\n",
       "\n",