anders_CPH said:The distinction that resolves most of these threads is between what is true on average and what is true for one person.
Coming at anders_CPH’s question from a different direction. Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the correction. That is slower than asserting, and it is the only version that survives being wrong.
If somebody has the primary source to hand I would rather cite it than paraphrase it.