title: What are 25%,50%,75% values when we describe a grouped dataframe?
body: <p>I am going through pandas groupby docs and when I groupby on particular column as below:</p>
  
  <p>df:</p>
  
  <pre><code>     A      B         C         D
  0  foo    one -0.987674  0.039616
  1  bar    one -0.653247 -1.022529
  2  foo    two  0.404201  1.308777
  3  bar  three  1.620780  0.574377
  4  foo    two  1.661942  0.579888
  5  bar    two  0.747878  0.463052
  6  foo    one  0.070278  0.202564
  7  foo  three  0.779684 -0.547192
  
  grouped=df.groupby('A')
  grouped.describe(A)
  </code></pre>
  
  <p>gives</p>
  
  <pre><code>              C                      ...         D                    
            count      mean       std  ...       50%       75%       max
  A   B                                ...                              
  bar one     1.0  0.224944       NaN  ...  1.107509  1.107509  1.107509
      three   1.0  0.704943       NaN  ...  1.833098  1.833098  1.833098
      two     1.0 -0.091613       NaN  ... -0.549254 -0.549254 -0.549254
  foo one     2.0  0.282298  1.554401  ... -0.334058  0.046640  0.427338
      three   1.0  1.688601       NaN  ... -1.457338 -1.457338 -1.457338
      two     2.0  1.206690  0.917140  ... -0.096405  0.039241  0.174888
  </code></pre>
  
  <p>what 25%,50%,75% signifies when described?
  a bit of explaination please?</p>