Find a total value using roster data

@Jaime , consider the example

https://designer.mysurvey.solutions/questionnaire/details/753db7890bca42af8f5e4bac685a7c5b/chapter/1b1cdb1353fb4c75ba42fa985a4a3b7c/group/1b1cdb1353fb4c75ba42fa985a4a3b7c

which shows how you can find the total of an attribute in a roster.

Best, Sergiy