AVERAGE
Requires: Write access to configure a questionnaire calculation.
Calculates an arithmetic mean. Input: nonempty numeric lists. Output: one numeric value. Example: [2, 4, 6] → 4.
With Per item off, all selected numeric values contribute equally. With it on, each selected input list gets its own mean; Value is unused. An empty aggregate returns 0.
Two-list example: select A = [2, 4] and B = [6]. Aggregate: (2 + 4 + 6) / 3 = 4. Per item: A becomes [3], B becomes [6]; it is not a mean of the two list means.