I have figured a way using my own calculated confidence intervals to use stacked area to shade the wanted band. I'd still like to know if there is a way to use Tableau's calculations? Again, I wouldn't want the reference line to be a whole average, but average of January 2015-2017 rates, then average of February 15-17 rates, etc.
1 of 1 people found this helpful
If you make the Month pill on Columns a Discrete (Blue)
and choose to calculate Ref Lines per Cell, you may get it.
Thank you. This solved that question. However, it looks like it's better if I calculate my own confidence intervals display wise. I can smooth out the shading better.
As you wish :-)