title: How to convert a series into an index of another series, aligned by their indexes
body: <p>I have this series:</p>
  
  <pre><code>dealer      certificate_status brand_kia 
  aeropuerto      NO               False     22 days
                                   True      29 days
  Galerías         SI              False     59 days
                   NO              False     34 days
  </code></pre>
  
  <p>And I have another series:</p>
  
  <pre><code>dealer
  aeropuerto    36 days
  Galerías      41 days
  </code></pre>
  
  <p>How can I place the values of the last series as an index of the first series, but with an average name.
  It would be like this:</p>
  
  <pre><code>dealer       average     certificate_status    brand_kia 
  aeropuerto    36 days           NO              False     22 days
                                                  True      29 days
  Galerías      41 ays            SI              False     59 days
                                  NO              False     34 days
  </code></pre>
  
  <p>It is possible to make this movement. Thanks for your help.</p>