title: Meaning of statsmodels OLS return.params
body: <p>I am trying to do linear regression with OLS and <code>Res.params</code> has retruned me a 2x2 array. 
  I know the <code>.params[0][1]</code> and <code>.params[1][1]</code> are the beta and constant of the regression. However, what's the meaning for <code>.params[0][0]</code> and <code>.params[1][0]</code> ?</p>
  
  <p>My implementation: </p>
  
  <pre><code>import statsmodels.api as sm
  X = np.arange(0, 20)
  X = sm.add_constant(X)
  Y = (X * 3) + 8
  Res = sm.OLS(Y, X).fit()
  Res.params
  array([[  1.10000000e+01,   8.00000000e+00],
         [  5.37764278e-17,   3.00000000e+00]])
  </code></pre>
  
  <p>Questions:</p>
  
  <ol>
  <li>What is the meaning of those values?</li>
  <li>How can I change my implementation, so it can return the array with beta and constant only?</li>
  </ol>