Wired magazine writes about a statistician, Mohan Srivastava, who figured out how to beat Ontario’s Tic Tac Toe lottery game:
The apparent randomness of the scratch ticket was just a facade, a mathematical lie. And this meant that the lottery system might actually be solvable, just like those mining samples. “At the time, I had no intention of cracking the tickets,” he says. He was just curious about the algorithm that produced the numbers. Walking back from the gas station with the chips and coffee he’d bought with his winnings, he turned the problem over in his mind. By the time he reached the office, he was confident that he knew how the software might work, how it could precisely control the number of winners while still appearing random. “It wasn’t that hard,” Srivastava says. “I do the same kind of math all day long.”
That afternoon, he went back to work. The thrill of winning had worn off; he forgot about his lunchtime adventure. But then, as he walked by the gas station later that evening, something strange happened. “I swear I’m not the kind of guy who hears voices,” Srivastava says. “But that night, as I passed the station, I heard a little voice coming from the back of my head. I’ll never forget what it said: ‘If you do it that way, if you use that algorithm, there will be a flaw. The game will be flawed. You will be able to crack the ticket. You will be able to plunder the lottery.’”
I thought this would be an article about how random number generators, but it’s not. It’s closer to the problem McDonald’s has with its Monopoly game – you have to let players think they are close to winning while denying them a prize.
The article does a nice job of laying out exactly how he figured the system out and why he didn’t, in his own words “plunder the lottery.” Go take a look.
(h/t Flowing Data)