I've been participating in Makeover Monday for a few weeks now, and this week I was determined to use calculated fields. 

 

My first thought was to do something along a control chart vein.  Tableau provides ways to show the average along with the upper and lower limits, but a couldn't find a way to show a process shift with new averages, etc. within the chart.  I resisted the urge to manipulate the data in Excel and managed to break the data into ranges.  And then I hit a wall.  There was no way to turn my calculated field into a dimension I could use to define the ranges in the chart.  I'm now beginning to see why there is some data manipulation tool listed along with Tableau in job postings.