title: Python pandas boxplot from dataframe
body: <p>I have the following dataframe, which has a multiindex. I thought I could groupby run then create a boxplot to show the variance between the different runs, but that doesn't seem to work.</p>
  
  <pre><code>             beta
  n   run 
  n1  run1    -2.301871e-05
      run2     2.45619e-05
      run3     3.413542e-05
      run4     5.23709e-06
      run5     2.313496e-05
  n2  run1     -2.96116e-06
      run2    -4.626588e-06
      run3    -4.463705e-06
      run4    -5.827251e-06
      run5    -3.127893e-06
  n3  run1    -3.196585e-06
      run2    -3.020926e-06
      run3    -2.264738e-06
      run4    -6.599127e-07
      run5    -3.301398e-06
  n4  run1    -3.509957e-07
      run2     -4.88517e-07
      run3     2.51758e-05
      run4     1.097775e-05
      run5    -9.213195e-07
  n5  run1    -5.393409e-07
      run2    -1.147589e-06
      run3     -1.07985e-06
      run4     8.075297e-06
      run5     4.471477e-06
  </code></pre>
  
  <p>how do I create a boxplot from it?</p>