title: How do I define a Standard Deviation function in Pentaho Schema Workbench
body: <p>I'm building an OLAP Analysis with Pentaho's BI Suite (Community Edition). Many of my measures are standard deviations of the variables in my fact tables.</p>
  
  <p>Does someone has a tip on how to define a Standard Deviation aggregation function in Schema Workbench? Lot's of my jobs could benefit of it.</p>
  
  <p>Thanks in advance!</p>