I'm a little surprised such rudimentary math made it to the front page of Hacker News (at #2 even). Maybe it's time to pick a FP language and make posts about it all day, to scare some people away?
Please no one believe this post, it uses dubious statistics.
If you want to learn more about how to hedge bets, read about things like moment theory or the Kelly criterion.
Also, taking a measure like variance would be much more meaningful than just the spread of the payoff.