4 ms·

I work in this field (different experiment); that's not really true. In particle physics, sigma denotes "significance", not standard deviation. Technically what

I work in this field (different experiment); that's not really true. In particle physics, sigma denotes "significance", not standard deviation. Technically what we're quoting as "sigmas" are "z-values", where z=Phi^{-1}(1 - p), where Phi^{-1} is the inverse CDF of the Normal distribution and p is the p-value of the experimental result. So, 7 sigma is defined to be the level of significance (for an arbitrary distribution) corresponding to the same quantile as 7 standard deviations out in a Normal distribution.

Aachen 5y ago
I'm one of those dumb people that didn't have much math or greek in school, so this weird-looking o in the title was quite literally Chinese to me. Now it turns out that people in the know also misunderstood its intended meaning because it's in a different field. For years I've argued foreign symbols and single-letter variable names mainly seem to serve to keep a walled garden around the sciences, and this was cemented when I eventually went for a master's degree and I was expected to do this as well in compsci to get a better grade even if there is no advantage. If we could just write what we mean, I suspect people would find that more useful even if it makes it look less cultivated and more mainstream. (To be clear, this is not criticism on the person I'm replying to, but split between the author of this specific title and most of the sciences as a whole because it's a universally supported barrier (if only ever implicitly), aside from a few science communicators.) Edit: scrolled further in the thread. Looks like I'm not the only one, though this person at least knew to name the sigma: https://news.ycombinator.com/item?id=30955621 https://news.ycombinator.com/item?id=30955621
- LudwigNagasena 5y ago
  Notation is the easiest (and a very helpful) part of physics, statistics and probably all other scientific areas. That just sounds like an excuse.
  - Aachen 5y ago
    I've heard my complaint be called an excuse before, but consider that it's also the first barrier. Not a big one when you already decided to take a course, when you're seriously interested, when you just look them up and soon enough you know the conventions in the field. That's different from casual reading on HN, though. And tell me, are scientists not a class that is looked up to where you live? The common Joe might not explicitly say so, but if someone is a "scientist" then you don't expect them to be stupid or muck out stalls; they do have some real status. This doesn't come from doing things that seem like any common Joe can do it, yet a lot of the work is just that. Once you start paying attention to how often "new research" in the news amounted to a big survey and very basic statistics, or playing around with a Kinect in a train station to learn about walking patterns, it doesn't seem so different from what regular HN readers do for a living. If you take the paper behind such a survey, it'll turn out to be full of complexity that is a lot harder to get through than necessary. It could be a lot more accessible, but then they would lose status. It seems to me that brevity is the real excuse here. Moreover, if it were just about symbols but papers were otherwise accessibly written (to reasonable extents, obviously), that would be different still. This is not the case. Appearances are probably also important for funding. I'd bet that if you submitted same proposal twice, once phrased in a convoluted way and once phrased in a "we're gonna blow up some material multiple times and see how far the shards fly" style, a number of times to independent funding committees, there would be a statistically significant correlation with which proposal gets funded.
    - LudwigNagasena 5y ago
      Why does opaque bad research form psychology, social sciences or paleoclimatology constantly gets media attention and support? I absolutely do not believe it has anything to do with notation. And let’s be real. If you couldn’t understand sigma notation in school, the chances that you would comprehend complex science are very low no matter what kind of verbiage or, as it often would be more apt to say, verbal garbage it is wrapped in. I absolutely agree with you that oftentimes bad research is disguised with ten dollar words. And oftentimes it is disguised with convenient agenda (no matter how true or good this agenda is by itself). But I don’t believe it has anything to do with Greek letters.
- doliveira 5y ago
  Do you want to go back to writing equations with words?
  - Aachen 5y ago
    Just like I code in a programming language, I'm not proposing to turn everything into English prose. Rather, using (abbreviated) names for variables and perhaps a bit more common language in papers (but that's maybe a separate topic). Also I'm not sure what you mean by "back", is it referring to what we iirc called story exercises in Dutch primary school ("Jan goes to the store and buys seven ladders, then sells three..." etc.) or was this a thing a few hundred years ago or so?
    - mhh__ 5y ago
      Writing formal mathematics as programming languages is basically what automated theorem provers do. The proofs are mostly unreadable. Mathematical notation really isn't that hard as long as you treat it as its own thing and learn it properly rather than trying to use a likely imperative model of computing programming as a reference point.
    - doliveira 5y ago
      Yeah, imagine making a calculation or transforming a complex formula with words and full sentences. Algebraic notation was a pretty big invention for a reason. For instance, the reason why we use single letters and indexes is so it's not confused with products. Try to write and manipulate the Schrodinger equation with words. Imagine solving the hydrogen atom, it already takes like 50 pages with algebraic notation... And I don't really understand the "I didn't do math and Greek in School". I barely had a foreign language, but if you're actually learning the concept you memorize the letter as well. You can't understand what a wave function is and then not remember that its symbol is Psi. And if you don't know what a wave function is, it won't help to write derivate_2nd_order(waveFunction, time). EDIT: obviously we're not talking about stories to teach newcomers, you're talking about writing equations in scientific articles and books with words.
      - 5y ago
- cshimmin 5y ago
  It is just a convention, specifically for interpreting and presenting experimental results. We also use sigma to represent standard deviation in other contexts, of course. Sometimes it represents Pauli spinor matrices. Sometimes it's an index for spacetime tensors. Life would be hell for any practitioner without single-letter abbreviations. In fact, we like them so much, that's why we adopted the greek letters (we ran out of alphabet). And, for better or for worse, convention runs deep in scientific literature. In practice it reduces a lot of redundancy, makes it more efficient for researchers to skim and understand results. But the cost is a years-long learning curve to break into any scientific field's literature. FWIW, the linked article is from the journal Science, which is a technical publication. Often "sigma" is omitted in sci-comm articles, or at least is translated for the reader. They will say something like "there is a one in X million chance this is a fluke".
  - jacquesm 5y ago
    Those APL people may have been on to something after all!
  - indymike 5y ago
    Looking up from my screen filled with sanity saving conveniences like having to type /sigma to get a really smart looking lower case greek character to display so the masses can't make sense of my math.
    - BlueTemplar 5y ago
      Could be "Alt+G + s" : http://norme-azerty.fr/en/ http://norme-azerty.fr/en/
- nine_k 5y ago
  Much of these formulae used to be handwritten, and still are handwritten at a blackboard / whiteboard in physics classes. It's much easier to draw a fancy symbol by hand than write several simple letters quickly and legibly, and it also takes much less space. We've been having the privilege to write using computers for last 20-25 years, when PCs became widespread, relatively cheap, and running good enough software. And this is outside the lecture hall settings anyway.
  - Aachen 5y ago
    > Much of these formulae used to be handwritten, and still are handwritten at a blackboard / whiteboard in physics classes. That is honestly the best argument I've ever heard (you're the first I see mention it). With as much as I hate writing rather than typing, I can see the point there actually. Maybe this practice is not as wholly stemming from elitism as it first seemed.
- ajkjk 5y ago
  Don't agree with this, it took a few weeks of physics classes to get used to using greek letters as variables, and without them you'd drown in re-used letters.
  - Aachen 5y ago
    > it took a few weeks of physics classes to get used to using greek letters as variables That's a very small price if you're actually involved with physics regularly, but HN is a relatively mainstream place. I had physics for 4 years in school but this wasn't part of the curriculum. At some point I asked why we were told (seemingly-to-me falsely) that there were only 3 phases of matter when on google videos I had seen something about superfluidity. The teacher made a joke about my stumbling over that word and then the buzzer went so... that's the kind of physics we had. And that's for someone who went to school in one of the richest (GDP per capita) and most-developed (HDI) countries in the world. I don't know what it's like for anyone tuning in from a less well-off place, or for someone who had physics decades ago without refreshers (for me it's only a bit more than one decade now). Something tells me I should have looked for a statistics paper that replaced GDP and HDI with some random symbol and used that instead. That's the kind of thing you're promoting and I just don't see why. TLAs aren't everything but they're better than single letters. > without them you'd down in re-used letters eh, literally the opposite? Using (abbreviated) names you'd not drown in re-used letters.
    - ajkjk 5y ago
      well the abbreviated names include the letters, you can get in trouble when questions tend to have many symbols appended together. I should clarify, though, that I was thinking of college physics classes, which are definitely more mature, both about exploring new knowledge instead of memorizing facts, and about learning to actually speak in the experts' language. Using symbols for common concepts without defining them is, however, absurd. (Not counting a few -- c, e, hbar, m, maybe q?)
- bigbillheck 5y ago
  When you see a symbol you don't recognize, like 'σ', you can just paste it into google and it'll tell you. I personally don't see why greek letters are such a big sticking point, there's only 24 of them, and unlike Greek children you don't have to learn them all in one go.
- enchiridion 5y ago
  I disagree with the parent post about the use of Greek letters, but it seems like a valid point worth of discussion. Certainly in the spirit of HN. I’ve seen an increasingly worrying trend of using downvotes to voice disagreement, rather than as the intended purpose as a kind of crowd-based moderation. And before anyone lambasts me for complaining about downvotes, I’m complaining about the trend, where the above comment is just a exemplar.
  - tzs 5y ago
    > I’ve seen an increasingly worrying trend of using downvotes to voice disagreement, rather than as the intended purpose as a kind of crowd-based moderation. Actually Paul Graham did intend downvotes to express disagreement. The theory was that if people could express disagreement by downvoting there would be less people posting insubstantial comments to disagree.
- _moof 5y ago
  If you don't know what the Greek letter sigma means, you aren't going to know what the phrase "standard deviation" means, either. The notation isn't the issue. The issue is you can't fit stats 101 into a headline, and there's no getting around that.
habitue 5y ago
> Surprisingly, the researchers found that the mass of the boson was significantly higher than the SM predicts, with a discrepancy of 7 standard deviations. —JS This is from the editor's comment at the top of the article, I'm guessing it was a mistake, but that might be why people are getting thrown off by it

Aachen 5y ago

I'm one of those dumb people that didn't have much math or greek in school, so this weird-looking o in the title was quite literally Chinese to me. Now it turns out that people in the know also misunderstood its intended meaning because it's in a different field. For years I've argued foreign symbols and single-letter variable names mainly seem to serve to keep a walled garden around the sciences, and this was cemented when I eventually went for a master's degree and I was expected to do this as well in compsci to get a better grade even if there is no advantage. If we could just write what we mean, I suspect people would find that more useful even if it makes it look less cultivated and more mainstream. (To be clear, this is not criticism on the person I'm replying to, but split between the author of this specific title and most of the sciences as a whole because it's a universally supported barrier (if only ever implicitly), aside from a few science communicators.) Edit: scrolled further in the thread. Looks like I'm not the only one, though this person at least knew to name the sigma: https://news.ycombinator.com/item?id=30955621 https://news.ycombinator.com/item?id=30955621

LudwigNagasena 5y ago
Notation is the easiest (and a very helpful) part of physics, statistics and probably all other scientific areas. That just sounds like an excuse.
- Aachen 5y ago
  I've heard my complaint be called an excuse before, but consider that it's also the first barrier. Not a big one when you already decided to take a course, when you're seriously interested, when you just look them up and soon enough you know the conventions in the field. That's different from casual reading on HN, though. And tell me, are scientists not a class that is looked up to where you live? The common Joe might not explicitly say so, but if someone is a "scientist" then you don't expect them to be stupid or muck out stalls; they do have some real status. This doesn't come from doing things that seem like any common Joe can do it, yet a lot of the work is just that. Once you start paying attention to how often "new research" in the news amounted to a big survey and very basic statistics, or playing around with a Kinect in a train station to learn about walking patterns, it doesn't seem so different from what regular HN readers do for a living. If you take the paper behind such a survey, it'll turn out to be full of complexity that is a lot harder to get through than necessary. It could be a lot more accessible, but then they would lose status. It seems to me that brevity is the real excuse here. Moreover, if it were just about symbols but papers were otherwise accessibly written (to reasonable extents, obviously), that would be different still. This is not the case. Appearances are probably also important for funding. I'd bet that if you submitted same proposal twice, once phrased in a convoluted way and once phrased in a "we're gonna blow up some material multiple times and see how far the shards fly" style, a number of times to independent funding committees, there would be a statistically significant correlation with which proposal gets funded.
  - LudwigNagasena 5y ago
    Why does opaque bad research form psychology, social sciences or paleoclimatology constantly gets media attention and support? I absolutely do not believe it has anything to do with notation. And let’s be real. If you couldn’t understand sigma notation in school, the chances that you would comprehend complex science are very low no matter what kind of verbiage or, as it often would be more apt to say, verbal garbage it is wrapped in. I absolutely agree with you that oftentimes bad research is disguised with ten dollar words. And oftentimes it is disguised with convenient agenda (no matter how true or good this agenda is by itself). But I don’t believe it has anything to do with Greek letters.
doliveira 5y ago
Do you want to go back to writing equations with words?
- Aachen 5y ago
  Just like I code in a programming language, I'm not proposing to turn everything into English prose. Rather, using (abbreviated) names for variables and perhaps a bit more common language in papers (but that's maybe a separate topic). Also I'm not sure what you mean by "back", is it referring to what we iirc called story exercises in Dutch primary school ("Jan goes to the store and buys seven ladders, then sells three..." etc.) or was this a thing a few hundred years ago or so?
  - mhh__ 5y ago
    Writing formal mathematics as programming languages is basically what automated theorem provers do. The proofs are mostly unreadable. Mathematical notation really isn't that hard as long as you treat it as its own thing and learn it properly rather than trying to use a likely imperative model of computing programming as a reference point.
  - doliveira 5y ago
    Yeah, imagine making a calculation or transforming a complex formula with words and full sentences. Algebraic notation was a pretty big invention for a reason. For instance, the reason why we use single letters and indexes is so it's not confused with products. Try to write and manipulate the Schrodinger equation with words. Imagine solving the hydrogen atom, it already takes like 50 pages with algebraic notation... And I don't really understand the "I didn't do math and Greek in School". I barely had a foreign language, but if you're actually learning the concept you memorize the letter as well. You can't understand what a wave function is and then not remember that its symbol is Psi. And if you don't know what a wave function is, it won't help to write derivate_2nd_order(waveFunction, time). EDIT: obviously we're not talking about stories to teach newcomers, you're talking about writing equations in scientific articles and books with words.
    - 5y ago
cshimmin 5y ago
It is just a convention, specifically for interpreting and presenting experimental results. We also use sigma to represent standard deviation in other contexts, of course. Sometimes it represents Pauli spinor matrices. Sometimes it's an index for spacetime tensors. Life would be hell for any practitioner without single-letter abbreviations. In fact, we like them so much, that's why we adopted the greek letters (we ran out of alphabet). And, for better or for worse, convention runs deep in scientific literature. In practice it reduces a lot of redundancy, makes it more efficient for researchers to skim and understand results. But the cost is a years-long learning curve to break into any scientific field's literature. FWIW, the linked article is from the journal Science, which is a technical publication. Often "sigma" is omitted in sci-comm articles, or at least is translated for the reader. They will say something like "there is a one in X million chance this is a fluke".
- jacquesm 5y ago
  Those APL people may have been on to something after all!
- indymike 5y ago
  Looking up from my screen filled with sanity saving conveniences like having to type /sigma to get a really smart looking lower case greek character to display so the masses can't make sense of my math.
  - BlueTemplar 5y ago
    Could be "Alt+G + s" : http://norme-azerty.fr/en/ http://norme-azerty.fr/en/
nine_k 5y ago
Much of these formulae used to be handwritten, and still are handwritten at a blackboard / whiteboard in physics classes. It's much easier to draw a fancy symbol by hand than write several simple letters quickly and legibly, and it also takes much less space. We've been having the privilege to write using computers for last 20-25 years, when PCs became widespread, relatively cheap, and running good enough software. And this is outside the lecture hall settings anyway.
- Aachen 5y ago
  > Much of these formulae used to be handwritten, and still are handwritten at a blackboard / whiteboard in physics classes. That is honestly the best argument I've ever heard (you're the first I see mention it). With as much as I hate writing rather than typing, I can see the point there actually. Maybe this practice is not as wholly stemming from elitism as it first seemed.
ajkjk 5y ago
Don't agree with this, it took a few weeks of physics classes to get used to using greek letters as variables, and without them you'd drown in re-used letters.
- Aachen 5y ago
  > it took a few weeks of physics classes to get used to using greek letters as variables That's a very small price if you're actually involved with physics regularly, but HN is a relatively mainstream place. I had physics for 4 years in school but this wasn't part of the curriculum. At some point I asked why we were told (seemingly-to-me falsely) that there were only 3 phases of matter when on google videos I had seen something about superfluidity. The teacher made a joke about my stumbling over that word and then the buzzer went so... that's the kind of physics we had. And that's for someone who went to school in one of the richest (GDP per capita) and most-developed (HDI) countries in the world. I don't know what it's like for anyone tuning in from a less well-off place, or for someone who had physics decades ago without refreshers (for me it's only a bit more than one decade now). Something tells me I should have looked for a statistics paper that replaced GDP and HDI with some random symbol and used that instead. That's the kind of thing you're promoting and I just don't see why. TLAs aren't everything but they're better than single letters. > without them you'd down in re-used letters eh, literally the opposite? Using (abbreviated) names you'd not drown in re-used letters.
  - ajkjk 5y ago
    well the abbreviated names include the letters, you can get in trouble when questions tend to have many symbols appended together. I should clarify, though, that I was thinking of college physics classes, which are definitely more mature, both about exploring new knowledge instead of memorizing facts, and about learning to actually speak in the experts' language. Using symbols for common concepts without defining them is, however, absurd. (Not counting a few -- c, e, hbar, m, maybe q?)
bigbillheck 5y ago
When you see a symbol you don't recognize, like 'σ', you can just paste it into google and it'll tell you. I personally don't see why greek letters are such a big sticking point, there's only 24 of them, and unlike Greek children you don't have to learn them all in one go.
enchiridion 5y ago
I disagree with the parent post about the use of Greek letters, but it seems like a valid point worth of discussion. Certainly in the spirit of HN. I’ve seen an increasingly worrying trend of using downvotes to voice disagreement, rather than as the intended purpose as a kind of crowd-based moderation. And before anyone lambasts me for complaining about downvotes, I’m complaining about the trend, where the above comment is just a exemplar.
- tzs 5y ago
  > I’ve seen an increasingly worrying trend of using downvotes to voice disagreement, rather than as the intended purpose as a kind of crowd-based moderation. Actually Paul Graham did intend downvotes to express disagreement. The theory was that if people could express disagreement by downvoting there would be less people posting insubstantial comments to disagree.
_moof 5y ago
If you don't know what the Greek letter sigma means, you aren't going to know what the phrase "standard deviation" means, either. The notation isn't the issue. The issue is you can't fit stats 101 into a headline, and there's no getting around that.

habitue 5y ago

> Surprisingly, the researchers found that the mass of the boson was significantly higher than the SM predicts, with a discrepancy of 7 standard deviations. —JS This is from the editor's comment at the top of the article, I'm guessing it was a mistake, but that might be why people are getting thrown off by it