The system
If there is one defining mathematical characteristic of humans, it’s that they are terrible at estimating probability, just awful at it.
I include myself in that statement, I’m terrible at games of chance… I regularly lose my quarterly poker stake (£3) because of some terrible maths going on inside my head.
There’s a classic textbook exercise that asks – There are 30 people in a room, what are the chances of two of them sharing a birthday? I’ll let you think about that…
I also heard that you have a greater chance of being killed by a refrigerator than you have of winning the lottery jackpot… 1 in 13,983,816. Judging by the number of people you see queuing up to buy a lottery ticket you would think that refrigerators would be banned by now.
Even my old maths teacher made a fundamental mistake when he said that he was tempted to take a bomb onto a plane since the probability of there being two independent bombs on the same plane were quite small… actually, I think it was a bluff. He also used to host a Christmas poker game and would regularly fleece the students.
So I’m poor at calculating chance, and I had a teacher who stood to profit from the ignorance of his students… what is the probability that he deliberately mislead us in order to supplement his salary?
justine on 
I would also have to be included in the “horrid at probability” bracket. Usually I just ignore it’s existence, and stay away from all ‘chancy’ things. This becomes a problem when watching the weather network…
The fact that the dice do not go in numerical order bothers me a LOT. I am a crazy person.
The 30 people in a room puzzle, do you want the odds of *exactly* 2 people sharing a birthday, or *2 or more* people sharing a birthday?
It doesn’t make a lot of difference… I make the answers to be 0.302% and 0.310% respectively.
@Matt it’s actually greater than 50%
http://en.wikipedia.org/wiki/Birthday_paradox
Sorry Matt, it’s more like 75%.
(http://en.wikipedia.org/wiki/Birthday_problem)
Ok.. turns out I actually suck at probability too.
Curse you with your problematic probability problem!
why does problematic probability even
matter? who cares if two people in the
same room share the same birthday? it
doesn’t matter to the cosmos either way.
what’re the odds both birthdays
share the same person?
The odds that both birthdays share the same person…. born twice? Does that make them born-again Christians?
Oh man! I spilt my coffee when I read that one! Awesome ^^
The probability of everything is 50/50, cause it will either happen or it won’t. ¬_¬
So… fair 6 sided die
odds of rolling a 1: 50%
odds of rolling a 2: 50%
odds of rolling a 3: 50%
odds of rolling a 4: 50%
odds of rolling a 5: 50%
odds of rolling a 5: 50%
================
Total probability: 300%
Interesting…
Ah crapnuts, typo there - last line should be 6
Probability of inserting a typo whilst enjoying a bout of ‘reductio ad absurdum’ - 100%
i think a 300% chance of something
happening or not is a fair estimation.
it doesn’t have to be exact.
Yup I’m with Seraphine… or it’s just 3x more likely to be 50% than not?
Argh, my God! I’ve spent months arguing with my maths teacher, my friends and some sixth formers that you can’t get more than 100%, and here you are just making claims all over the place that you can!
It really irritates me. “per cent” means “as per one hundred” so 100% should the most percentage you can get, but nooooo, people have to go making the word percent obsolete and thus subtley crushing the whole point of percentages. Why?!
On the other hand, I’m now determined to get 300% on my science exam in Wednesday…
First of all, I was joking about the 50/50 thing (though it works out in practice… think about it - after the dice is shot it was either a 4 or it wasn’t).
Secondly, you can indeed have more than 100% of something - if 100% is defined rigidly. It only means to compare as a ratio of occurrence “per 100″ so why couldn’t unemployment, say, be 200% of say the yearly average? It’s a ratio - just like 2/1 only expressed with a different symbol from /. Indeed there is ‰ (per 1000 - “permille”) and ? (per 10,000 - “permyriad”). It’s just a ratio, and not a magic one. Feel better?
As for getting more than 100% on an exam, we did that routinely with extra credit questions and optional questions and the like… so by all means. : )
Apparently Adam doesn’t support the “permyriad” I shall write my erm, “minister of maths?” “local math congressperson?”
I’m with you - can’t get more than 100%
Besides, if every side of a die had a 50% chance of coming up, then between them any 2 chosen sides would have a probability of 100% i.e. certainty.
So every time you rolled a die it would be 100% certain that you get either a 1 or a 2
AND 100% certain that you get either a 3 or a 4
AND 100% certain that you get either a 5 or a 6
and every other combination…
So every time you roll a die, several mutually exclusive events would all be certain to happen. Which is impossible (not just improbable, impossible).
You need to read up on your quantum physics.
Seriously tho, I only meant it as:
probability of 4: 50%
probability of everything else: 50%…. but again… it’s a joke. so um….
um…. should we keep arguing about it? Are you having fun?
I’ll continue if you want to.
Eh, why not… little nonsensical argumentation never hurt anyone. Except that one guy… but that was just that one time, it probably won’t happen again. Unless you’ve fiddled with the probability.
It cannot be “50% it happens, 50% it doesn’t” just because after the fact you know one thing happened and the other didn’t, probability has to apply to things that haven’t happened yet, so we need some more fractions. Fact is, if you roll a die, it won’t come up 4 50% of the time (excepting loaded dice).
Since I have no rebuttal can I switch to ad homonym attacks now?
You do whatever you need to
My subtle play on words is wasted… : (
I myself have a philosophy that improbable is not the same thing as impossible. For instance, a popular example in these probability comparisons is that someone is “as likely to be struck by lightning”, but Central Florida gets more lightning strikes than anywhere in the US (we call it Lightning Alley), so does that mean you’re more likely to win the lottery here? The odds of winning the lottery are so infinitesimal that it’s not really worth wasting energy on, but people DO win it, people do get struck by lightning, highly unlikely things happen just as often as the probabilities promise, but people have such a fuzzy sense of probability that they discount them completely.
Of course, this logic doesn’t hold any water. It’s never actually a good idea to bet on a long-shot, that’s why it’s called a long-shot.
Also part of the reason I have this philosophy, besides the fact that I fall well outside the average in almost every way, is that when I used to drink 20oz sodas a lot I used to constantly win free sodas on those under-the-cap contests. Like, every other soda. In fact I still probably would they just don’t do those contests so much anymore (they give you a code now you have to enter online, and I just never bother.) Illustrative of this, I just now won a free soda!
apparently the best way to play the lottery is to calculate how much you would likely spend throughout your lifetime, and spend it all on multiple tickets for one draw.
Now, you can never play the lottery again… but at least you stand the best chance of winning you’ll ever have.
That said, I too refuse to play the lottery. So that would be a lifetime total of 0.
There are a lot of ‘you have better odds of x than winning the lottery’ but my all-time favourite is that you have a better chance of taking a random stranger’s credit card and guessing their pin number.
improbability doesn’t hold any water.
it’s leaky as hell in a wicker handbasket.
The odds of at least two people in a room of 30 people sharing the same birthday are pretty good- if I remember correctly, they’re around 1 in 2 or thereabouts. The reason why most people get this wrong is that they select an arbitrary person and calculate the odds of another person in the room sharing that birthday- this results in a much lower probability because it doesn’t take into account the fact that there might be a separate grouping of two people who share the same birthday but don’t share it with the arbitrarily selected first person.
I’m not going to solve the problem myself right now, since I have to go catch a train. I’m sure you can find a solution on internet.
Indeed, with 30 people you actually get more ‘pairs’ of people than is blatantly obvious. this usual error comes with people thinking about birthdays in the 1 in 365 sense.
I read about the birthday problem a while ago, I believe that with anything past 28 people there is a > 50% chance of two of them sharing a birthday. It’s an interesting problem, kind of counter-intuitive, much like the ol’ monty hall riddle.
My favourite lottery is the “powerball” one we have here in oz. They draw the final ball from a separate barrel, which makes it something like five times harder to win, only most people don’t realise that.
The only way to win at gambling is to be the house. Or to load the dice
“The only way to win at gambling is to be the house. Or to load the dice”
Einstein said the only way to beat a roulette table is to cheat. Alby was a terror at cards and boardgames too… I once heard he had monopoly money shoved up his sleeves at all times, just in case.
just been reading your blog, by the way, great stuff, and I’ve added you to my reader.
the reason most people don’t win
at roulette is people bet against
themselves. they incorrectly believe
the more numbers they play, the
greater the chance of winning. the
truth is, the more numbers you play,
the greater the probability that
you will lose money (just as surely
as you’ll lose the longer you play).
As Derren Brown put it, “I don’t condone gambling of any sort unless you can cheat very effectively and stack the odds at least 90% in your favour”.
This sounds like my random discussion.
Is it random because the influencing factors are random, or is it random because we don’t know what the influencing factors are.
Big difference in definition, but most ppl ignore it.
Like chance.
We had a lotto draw last night worth AUD$50million.
According to several news broadcasts, an Australian has a higher chance of dieing from a snake bite or shark attack then winning the jackpot.
YAY for being Australian.
Snake bites and shark attacks are mostly avoidable, so I think they are bad comparisons.
“Snake bites and shark attacks are mostly avoidable.” – yup, I avoid them by living in a country that has very few sharks (and the ones we have are vegetarian) and the chance of snakebite is slim to none… unless you are referring to the rather nasty cider based cocktail that is available in all good biker bars.
no ben, it’s a fair comparison.
winning is avoidable too.
i know losers who go through
their entire lives without
winning anything.
I just remembered another maths teacher fact… he would introduce himself by his initials, RFB, and would ask students to guess what they stood for…
Rabid Fan Boy?
Rufus Fortuna Bananza. His parents were horrible to name him that. It was actually a dare from their old university friends to name their child something so ridiculous. In the 8th grade he introduced himself to a girl that he’d had his eye on for quite a while, and she laughed for near 2 hours. Ever since he decided on the RFB thing. Says it gives him an air of mystery, and no one gets it right anyway.
Poor Rufus Fortuna Bananza.
But people who see themselves as lucky actually are luckier.
Why? Because they see the oppurtunities presented to them, whereas the more pressimistic “unlucky” people don’t.
It’s quite interesting, actually.
Completely off topic here, but has anyone noticed that our name’s have shrunk? They’re miniscule!
I noticed!
I was a little disappointed until I realised it means I’ll get to know people by their symbol rather than their name.
Which I think is rather cool.
*Adam finds no reasonable explanation for the tiny names*
I’ll see if I can sort it out. Try not to strain your eyes in the meantime.
I figured you’d done it on purpose, for the very reason that Philippa pointed out.
Haha! The gods of the interwebz have spoken, and they prefer we know each other by abstract pictographic representation!
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