5 Replies Latest reply on Jan 28, 2010 1:59 PM by . fmalter

    Error bars

    Brad Langhorst

      Sure would be nice to display some error bars on scatter plots.

        • 1. Re: Error bars
          . HealthMaps

          Please add some error bar (confidence interval)  capability. I would imagine that business and finance folks would want at least a high-low-close chart for tracking stock prices.

           

          There is the capability to set as an aggregation option, the variance.  Which means that for some measures (the mean?) confidence intervals would be possible. Being able to see the confidence intervals is really a very important part of analysis. Tableau allows slicing and dicing data which is incredibly useful, but then the next step of being able to do a little inference would be a big help.

           

          But beyond that one needs the capacity to use their own calculated confidence intervals and display them.

           

          They are needed for trend plots and for bar charts.

          • 2. Re: Error bars
            guest contributor

            I fully support this idea.

            • 3. Re: Error bars
              Alex Blakemore

              You can do some of this now

              See  http://www.tableaucustomerconference.com/sessions/training/

               

              And then look at the workbook for the class called

              Means, Modes, Percentiles & Outliers: Using Tableau to Understand Distributional Data

               

              Check out the worksheet titled "Modern Box Plot"

               

              This example uses reference lines to show quartiles, but you could just as easily choose to show confidence intervals instead.

               

              This is not to say that Tableau couldn't improve its support for displaying confidence intervals. It takes a bit of a trick to get this chart to work (placing one dimension on the column shelf twice)

               

              But note one really nice feature. By plotting points with semi-transparent marks, you can get a very good impression of the distribution of the data, definitely better than you get from a traditional box plot.

              • 4. Re: Error bars
                . Jesus

                In a Research setting, the use of error bars is standard; you don't need to explain anything, you view the graphs, and that's it: Visualization at its best. Please consider adding this feature to future versions of Tableau.

                • 5. Re: Error bars
                  . fmalter

                  I can't find the workbook in the link Alex Blakemore provided. How can I add simple error bars to points in a line graph? Thx.