I don't think that the arithmetic mean is appropriate here (see my replies to two sibling comments) but rather the median. Your second point is a good one - cl

I don't think that the arithmetic mean is appropriate here (see my replies to two sibling comments) but rather the median. Your second point is a good one - clearly, funniness is subjective. On the other hand, I don't think my argument relies on the precise quantitative definition of funniness!