fixed pooled sd

Author: ericmjl

notebooks/03-instructor-two-group-iq.ipynb

@@ -236,8 +236,10 @@
     "    # Calculate the effect size and its uncertainty.\n",
     "    diff_means = pm.Deterministic('diff_means', mu_drug - mu_placebo)\n",
     "    pooled_sd = pm.Deterministic('pooled_sd', \n",
-    "                                 np.sqrt(np.power(sigma_drug, 2) + \n",
-    "                                         np.power(sigma_placebo, 2) / 2))\n",
+    "                                 np.sqrt(\n",
+    "                                     (np.power(sigma_drug, 2) + np.power(sigma_placebo, 2)) / 2\n",
+    "                                  )\n",
+    "                                 )\n",
     "    effect_size = pm.Deterministic('effect_size', \n",
     "                                   diff_means / pooled_sd)"
    ]