title: DataError: No numeric types to aggregate
body: <p>I am going to describe males and females groups by gender to visualize how Churn Rate (1-Retention Rate) looks like for each value.</p>
  <p><strong>My output</strong></p>
  <pre><code>df_data.groupby(by='gender')['Churn'].mean()
  
  
  
  error
  ---------------------------------------------------------------------------
  DataError                                 Traceback (most recent call last)
  &lt;ipython-input-46-75992efc6958&gt; in &lt;module&gt;()
  ----&gt; 1 df_data.groupby(by='gender')['Churn'].mean()
  
  1 frames
  /usr/local/lib/python3.7/dist-packages/pandas/core/groupby/groupby.py in mean(self, numeric_only)
     1396             &quot;mean&quot;,
     1397             alt=lambda x, axis: Series(x).mean(numeric_only=numeric_only),
  -&gt; 1398             numeric_only=numeric_only,
     1399         )
     1400 
  
  /usr/local/lib/python3.7/dist-packages/pandas/core/groupby/groupby.py in _cython_agg_general(self, how, alt, numeric_only, min_count)
     1051 
     1052         if len(output) == 0:
  -&gt; 1053             raise DataError(&quot;No numeric types to aggregate&quot;)
     1054 
     1055         return self._wrap_aggregated_output(output, index=self.grouper.result_index)
  
  DataError: No numeric types to aggregate
  </code></pre>