Having the 12 fields may be easiest - if you don't need to keep those entered values long-term. If that's the case, then do the 12 fields and then build a formula that show's "Current Month's Required Sample Size" and have it display the value of one of the 12 fields, based on the current Month.
Case(Month(Today()),
1,[January],
2,[February],etc...)
You can then use this Formula in the View mode and the other fields in Edit/Add
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Blake Harrison
bharrison@datablender.io
DataBlender - Quickbase Solution Provider
Atlanta GA
404.800.1702 /
http://datablender.io/------------------------------