But Choi's conclusions are more complicated, even if he's already put more thought into this than anyone in history by two paragraphs ago. As it's estimated that we each defecate once per day and urinate seven times a day on average, what we need here are graphs. So many graphs.
There is no excuse for not using little poop icons on that graph.
Basically, if the number of ladies in the house is equal to or greater than the number of dudes, the seat stays down, period. To make keeping the seat up worthwhile, men have to outnumber women by a certain ratio. For example, in a house with four guys, they only get to keep the seat up when there are two or fewer girls; for five guys, three or fewer girls (if you start adding in variables such as multiple bathrooms and proximity of bathrooms to males and females, then you'd need some kind of supercomputer to figure it out).
So there you go. Now we just need them to tell us which way we should hang the toilet paper roll and our relationships will be smooth sailing.