title: tableau divide one measure by another
body: <p>I have data like below in Tableau. </p>
  
  <pre><code>school  student marks
  a       xy      5
  a       xy      10
  a       ab      15
  b       cd      20
  b       cd      25
  a       cd      30
  </code></pre>
  
  <p>I want to find total marks, count of marks and average marks by student and school</p>
  
  <p>in case of the below two tables i was able to create first 3columns, how could i create the 4th column? 2nd and third columns are measures.
  Is it possible to perform a row level calculation?</p>
  
  <pre><code>student sum of marks    count of marks  average marks
  xy      15              2               7.5
  ab      15              1               15
  cd      75              3               25
  
  school  sum of marks    count of marks  average marks
  a       60              4               15
  b       55              2               27.5
  </code></pre>