1 Reply Latest reply on May 28, 2013 12:04 AM by Jim Wahl

    How to include Margin of Error in a histogram of US Census data?

    Bill Engelke

      I want to make a histogram of census data by county (in a given state)- (% of uninsured); the data have a Margin of Error; is there any way to show the estimate plus the upper and lower estimate limit on each histogram bar (similar to a candlestick plot)? I don't want to show 3 histograms for each, this becomes too busy. Any ideas?

        • 1. Re: How to include Margin of Error in a histogram of US Census data?
          Jim Wahl

          Hi Bill,


          You have a few options, depending on your data and what look you're after.


          You can create a candlestick style plot by using dual-axis and multiple mark types. Your first chart would be the histogram (bar chart in Tableau) and your second could be a gantt chart with the starting point being the lower margin of error value and the gantt size being the height of the margin (upper - lower). You can adjust the size of the gantt to have it match the width of the bars in the histogram or make it narrower.


          Another option would be to use a frequency polygon---with three lines.


          Or you could use Tableau's reference band functionality. Create a band per cell with the upper and lower margin of error specified in calculated fields.


          If you're still a bit stuck, post some sample data (ideally in an packaged Tableau file--save as twbx) and someone can put these examples together.