Mean is a popular statistical measurement to determine the average value of a sample, but it is not possible to create a custom variable for the mean age in ArcGIS Business Analyst Web App Comparison Reports. This is because the U.S. Census Bureau only provides summarized data from their overall data collection at a block group level using the smallest geographical unit with a population between 600 and 3000 people. Without access to the raw unsummarized data, it is not possible to create a custom variable for the mean age in Comparison Reports.
Note: For more information on creating Comparison Reports, refer to ArcGIS Business Analyst Web App: Create Comparison Reports .
As an alternative, use the median age. Median is a more accurate statistical calculation method because mean can be skewed by a single individual. Select 2020 Median Age (Esri), which is available in the Popular variables section on the Comparison Reports tab in Business Analyst Web App.
The image below shows the 2020 Median Age (Esri) displayed in ArcGIS Business Analyst Web App.