To add to what other people said: we're talking about criminal trials, here "on average" isn't enough. Criminal procedure requires such a high standard of certa

To add to what other people said: we're talking about criminal trials, here "on average" isn't enough. Criminal procedure requires such a high standard of certainty(proving without a reasonable doubt, unanimity of jurors) because unlike civil trials it actually sends people to jail. So being right "on average" isn't enough because we can't afford to punish innocent people, we would rather not punish a guilty person than wrongfully punish an innocent one.