Sample data will be appreciated on which we can take this further.
For example, I have the following 5 age groups: 'Under 5', 5-10', '10-15', '15-20', 'Over 20'. Each of these bins have a specific number of records. I want to add 2 age groups - 'Under 5' and '5-10' - and see what percentage of the total these two make up. So for the 'Under 5' category, there are 14 records, and for 5-10 there are 22 records, making a total of 36 records in the two bins. There are a total of 49 records in the data set among all 5 age groups. I want a calculation on Tableau that does this sum (14 + 36), and then will give me the percentage for 36/49 (73.37%). Hope this helps!
Will it be a static? I mean this age grps which you have mentioned as a Numerator will be fixed? (Under 5 and 5-10) Also it will be helpful if you can draw the output the way you want or simple % value will do the job?
Let me know about this.