Autistic Teen Picks First Two NCAA Rounds Perfectly | Hacker News Reader

Autistic Teen Picks First Two NCAA Rounds Perfectly

nbcchicago.com

8 pointspavel24 comments

Shouldn't the title say autistic teen and his older brother claim he picked a perfect bracket? There's no record of it from before the tournament started.

"CBSSports.com can not confirm Alex's entry -- the company doesn't track entries to their Bracket Manager program."

My collection of infinite monkeys almost hammered out a perfect manuscript for Hamlet last night. Unfortunately, they messed up Hamlet's monologue in Act 3 Scene 1: "To be or not to be, that is the question. Cornell is going to kick the crap out of Wisconsin."

The article misquotes the odds of picking the first two rounds correctly. 1 in 13,460,000 is the historical odds of picking the first 2 rounds correctly if you always picked the top seed in each game.

In other words: think of the tournament's seeding as a bracket filled out by the NCAA itself. There's only a 1 in 13 million chance that it will be right through the first 2 rounds.

What this kid did is amazing. Its more than the inevitable result of enough random guesses.

Hrm, hang on a second. That actually makes it sound substantially less impressive. There are five million people playing this year on ESPN alone. Even if we assume that only a quarter of them have guesses that are as predictive as the seed numbers, that would mean we'd only have to go a decade or so before we'd get a situation like this.

ESPN is a great example. This year no one predicted even the first round correctly, much less the first two. In fact, only 3 people out of 5 million got only one game wrong in the first round.

The main problem with your logic is that most people make the same choices. For example, only 1% of ESPN brackets had Cornell surviving the first 2 rounds this year, while 73% thought Kansas would make the championship.

To my knowledge, no one on ESPN.com has ever predicted all 65 games in the first 2 rounds correctly.

> The main problem with your logic is that most people make the same choices.

You are right, my analysis is terrible. Boom, inferiority admitted.

That would indeed be tough, considering there are only 48 games in the first 2 rounds.

His picks are not random events; therefore, you cannot calculate the odds of his picking the 48 winners so easily. Did he also pick the play-in winner (Arkansas Pine Bluff)? I doubt it. This could be a hoax unless he registered his picks at the start, and where he could not change them. Perhaps we've all been had.

The odds of winning the lottery are highly improbable yet every almost every week someone wins it.

That said if he is that good reliably, there is lots of money to be made on sports betting.

The lottery is a poor, if often used, comparison for the odds involved in picking the NCAA tournament correctly. Picking 2 rounds of the NCAA tournament perfectly is orders of magnitude harder than picking the winning lottery numbers.

For starters, in the lottery:

1) No selection (number) is better than another. i.e., the winners are random

2) Each round has no effect on the next

3) The conditions of the experiment will not change

The NCAA tournament is the opposite:

1) Some selections (teams) are clearly better than others. Furthermore, the tournament is structured to give the best teams the best chances of winning.

i.e., selection is not random.

2) Each round limits the possible outcomes of the next. To have a chance of picking Round 2 correctly, you must have already aced Round 1.

3) Each game can be affected by an unlimited number of variables. For instance, if John Wall gets hurt it would alter the chances of a Kentucky national championship. More subtly, so could a delayed flight.

Even picking the correct lottery numbers twice in a row is not a fair comparison, because the results of the first experiment have no bearing on the second.

Non-random events are generally a lot easier guess correctly at than random events. This is why people will do things like card count or use weighted dice / coins with two heads / tails, etc. This is also why SSL keys are generated from random data rather than weighted data.

I'd love to play the lottery if I knew certain balls were weighted more heavily than others.

If you think non-random events are difficult to predict, give me your longitude and latitude and I'll predict with in five minutes what time the sun will rise tomorrow. Want to bet $1000 against?

The real reason the it is more difficult is because the odds randomly are 1 in 4 billion for the first round, where as a lottery like the 6/49 is 1 in 13,983,816. However, the NCAA is not completely random, it would be difficult to discern what the real odds are but the fact that many players are within a couple games should give you some clue to the decrease in odds given the extra information.

If 100 million brackets are filled out and the realistic odds are 1 in 1.5 billion (given the extra information) then someone should fill out a perfect bracket every 15 years. If you look at the prizes being offered for a correct bracket, it should give you some indication as to the greatly reduced odds that one actually faces. If the odds are really 2^48 for a correct 2 round bracket then it would stand to reason that you could offer a 1 trillion dollar prize for a correct bracket with a ticket price of $1 and still have a house margin of 99.64%

100 - ((1 / ((2^48) / 1 trillion)) * 100) = 99.644

This simply isn't the case. (My math may be way off, I was never a stats major)

I heard before the tourney started that you'd have better odds to win the lottery, twice in one week than to pick a perfect bracket.

Yes, I'm pretty sure there are a total of 63 games to pick (including all rounds), so the odds of picking them all correct are 1 in 2^63. If 300 million Americans filled out brackets, the odds of anyone picking it perfectly are still 1 in 30,744,573,500.

And he picked two rounds in a row. Since all 64 teams could theoretically make it to the second round, the odds are more like:

1 / (2^126)

I'll have to leave it to Wolfram Alpha to expand that one:

http://www.wolframalpha.com/input/?i=1+%2F+%282^63+*+2^63%29

First round: 1 / 2^32 since there are 32 winners to pick, and 2 choices for each.

Second round: 1 / 4^16 since there are 16 winners to pick and 4 choices for each. But this assumes you can pick a loser from round 1. So, it's actually 1 / 2^16 since there are 16 winners to pick and 2 choices for each.

Picking 2 rounds correct is 1 / 2^32 * 1 / 2^16 = 1 / 2^48

Nice! Thank you.

One thing: "this assumes you can pick a loser from round 1"

You can pick a loser from Round 1, because all selections are made before any games are played. So it looks like its:

1 / 2^32 * 1 / 4^16

(And we should probably add another 1/2 term to account for the play-in game =)

No. The chance of being incorrect in the first round is factored into the first term (since that term is calculating the probability of picking an entirely correct first bracket). The second term need only represent the chance of picking correctly from the teams in the second round, given that the first round was correctly predicted.

In other words, it's a straightforward application of the chain rule for probabilities:

p(A,B) = p(A) * p(B|A)

I don't think we disagree. Mind bearing with me for a moment?

Probability of A (round 1 / selecting the right urn):

1 / 2^32 (32 games, 2 possible winners for each)

Probability of B (round 2:

1 / 4^16 (16 games, 4 possible winners for each)

Probability of A and B:

(1 / 2^32) * (1 / 4^16)

So it would appear the chain rule for probability agrees with my point. What am I missing?

Your second term is wrong. There are 16 matches in the second round, and you have a 1/2 chance of picking the winner in each, not a 1/4 chance.

The first term (.5^32) is the probability of picking all of the winners in round one (p(A)). The second term (p(B|A)), must be the probability of picking all the winners in round two, given that you picked correctly in round one. Again, that's .5^16, not .25^16.

You're right, thanks for explaining it. I still couldn't see it this morning, but I talked it out with my co-founder, and he got through to me.

Thanks for sticking with it.

No, "loser from round 1" means a team you picked to lose. That is, you can't have Team A beat Team Z in round 1 and Team B beat Team Y, then have Team Z beat Team Y in round 2.

> 1 in 2^63.

Assuming all teams have the same probability of winning. So, it's not nearly as bad as 2^63. Probably in any given game one team has a 0.66 chance of winning. That takes it down to a much more manageable 2^63 in 3^63.

Wait . . .

Purdue is +6000 to win the tournament btw.

or 60/1.

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