Added statsmodels example to section 4

Author: Christopher Fonnesbeck

4. Statistical Data Modeling.ipynb

@@ -1502,6 +1502,24 @@
      "metadata": {},
      "outputs": []
     },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "As with our least squares model, we can easily fit logistic regression models in `statsmodels`, in this case using the `GLM` (generalized linear model) class with a binomial error distribution specified."
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "logistic = sm.GLM(y, sm.add_constant(x), family=sm.families.Binomial()).fit()\n",
+      "logistic.summary()"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": []
+    },
     {
      "cell_type": "markdown",
      "metadata": {},

README.md

@@ -78,4 +78,4 @@ For those requiring extra assistance with installing packages, there will be a h
 [1]: http://nbviewer.ipython.org/urls/gist.github.com/fonnesbeck/5850375/raw/c18cfcd9580d382cb6d14e4708aab33a0916ff3e/1.+Introduction+to+Pandas.ipynb   "Introduction to Pandas"
 [2]: http://nbviewer.ipython.org/urls/gist.github.com/fonnesbeck/5850413/raw/3a9406c73365480bc58d5e75bc80f7962243ba17/2.+Data+Wrangling+with+Pandas.ipynb "Data wrangling with Pandas"
 [3]: http://nbviewer.ipython.org/urls/gist.github.com/fonnesbeck/5850463/raw/a29d9ffb863bfab09ff6c1fc853e1d5bf69fe3e4/3.+Plotting+and+Visualization.ipynb "Plotting and visualization"
-[4]: http://nbviewer.ipython.org/urls/gist.github.com/fonnesbeck/5850483/raw/1e6ff25f4cf5db3b78e0a3187d79a0fb7d93d563/4.+Statistical+Data+Modeling.ipynb "Statistical data modeling"
+[4]: http://nbviewer.ipython.org/urls/gist.github.com/fonnesbeck/5850483/raw/5e049b2fdd1c83ae386aa3205d3fc50a1a05e5b0/4.+Statistical+Data+Modeling.ipynb "Statistical data modeling"