(We tried it a couple times at two different banks. With n=2, our p value was < 0.05 :)
Is there some sort of standards document somewhere that outlines the minimum viable check? Because handwritten in crayon on a napkin... I don't think that even "technically" counts. At least not anymore.
But on the other hand, I suppose a payee could accept your Crayola-napkin-check and just punch the numbers into their electronic check submission system?