[HN Gopher] How the US Air Force Ditched the Average and Saved L...
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How the US Air Force Ditched the Average and Saved Lives
Author : elephant_burger
Score : 165 points
Date : 2022-07-02 08:27 UTC (14 hours ago)
(HTM) web link (mannhowie.com)
(TXT) w3m dump (mannhowie.com)
| Foomf wrote:
| I absolutely love this article, and I like to re-read it every
| once in a while. It talks about the same thing:
| https://www.thestar.com/news/insight/2016/01/16/when-us-air-...
| elephant_burger wrote:
| Thank you for sharing. This is the first chapter from Todd
| Rose's excellent book The End of Average. In the book, he also
| touches on the fascinating topic of context. For example there
| is no such thing as a person's average level of aggression - IF
| I am around my parents I tend to get aggressive, but IF I am
| around friends and strangers I am calm.
|
| https://www.penguin.com.au/books/the-end-of-average-97801419...
| giardini wrote:
| FWIW the face of the statue of the "the typical woman
| 'Norma'" at
| https://www.thestar.com/news/insight/2016/01/16/when-us-
| air-...
|
| resembles Dana Scully of The X-Files.
|
| I also enjoyed Todd Rose's book, which examines the history
| of (mis-)interpretations and (mis-)uses of the "average":
|
| _The End of Average_
|
| https://www.amazon.com/End-Average-Unlocking-Potential-
| Embra...
| leoc wrote:
| Even Rose's article (I haven't read his book yet so I can't
| really say about that) tiptoes around what was going on
| here. It wasn't just a naive application of statistics.
| Rose gets through the Norma story without mentioning
| eugenics once, but the whole episode is so obviously part
| of America's pre-WWII eugenics swoon. Beyond specific
| beliefs about politics, race or genetics, but linked to
| them, there was a whole _Zeitgeist_ , the collectivist
| spirit of the age that gave us Busby Berkeley musical
| numbers https://www.youtube.com/watch?v=ysvQ5MaUbd8 and the
| IBM company songbook
| https://www.networkworld.com/article/2333702/a-history-of-
| si... . This was a time when it was acceptable, indeed it
| was progressive, to be violently hostile to difference or
| defectiveness: see for example _War Against the Weak_
| https://waragainsttheweak.com/ and, maybe most especially,
| _The Black Stork_
| https://global.oup.com/academic/product/the-black-
| stork-9780... . And of course it's no coincidence that the
| pioneers of statistics tended to be particular fans of
| eugenics themselves.
|
| (I am not an expert on anything.)
| coldcode wrote:
| While its not averages, it is nonetheless interesting view of
| misleading statistical analysis:
| https://www.trevorbragdon.com/when-data-gives-the-wrong-solu...
| about WW2 airplane design.
| leoc wrote:
| Unfairly or not, the OP does feel like a summary of Todd Rose's
| own "When U.S. air force discovered the flaw of averages", an
| excerpt from _The End of Average_ , which you linked there.
| Rose's article has been strongly upvoted here several times
| over the years.
| cm2187 wrote:
| The other massive misuse of average I keep hearing is people
| referring to the life expectancy at the XVIII century. Yeah it
| was 40 something but not because it was very rare for people to
| reach 60, but because the average is dragged down by the high
| infant mortality rate. Once you reached 20, your life expectancy
| was a bit lower than today, but it was common for people to reach
| 60.
|
| And in general people are really bad at thinking in term of
| distributions. If you discuss averages or percentiles, people
| identify to that metric like if it applied to every individual of
| that distribution. That makes the debate on D&I particularly
| unproductive.
| mdp2021 wrote:
| It is helpful to say that at first quintile they died at around
| 10 years of age and at last quintile they died at around 70
| (with a median at 33). The average may remain 40, but you get a
| better idea of the distribution.
| kurupt213 wrote:
| Blood pressure medicine is probably one of the biggest factors
| in pushing adult life expectancy past 60. Antibiotics get all
| the credit but I think their biggest demographic impact was
| reducing child mortality from middle ear infections.
| ackfoobar wrote:
| > If you discuss averages or percentiles, people identify to
| that metric like if it applied to every individual of that
| distribution. That makes the debate on D&I particularly
| unproductive.
|
| Damore included a graph of overlapping bell curves in his
| document to illustrate this point. Yet quite a lot of critiques
| I saw don't seem to understand that.
| jameshart wrote:
| Overlapping bell curves are ripe for misinterpretation.
|
| Look at the male/female height graphs on
| https://www.usablestats.com/lessons/normal for example (among
| the first examples that google came up with).
|
| The thing that stands out is the difference between the bell
| curves - the area under the male height curve that is not
| under the female one. (Indeed, on this page, the way they
| drew their histogram version of the curve they explicitly
| drew attention to this area)
|
| But this area isn't representative of a meaningful
| population.
|
| It's just the sum of the _excess_ number of men of a given
| height over and above the number of women of the same height.
|
| Crucially, the vast majority of men accounted for within that
| population are still _shorter than some women_.
|
| Unless you are, according to these numbers, over 77" tall -
| ie, over 6'5" - then there exist women who are taller than
| you.
|
| Admittedly the population of people taller than you certainly
| skews heavily male - but for any randomly selected group of
| men, in most cases it is _possible_ to find a group of just
| as many women who are all taller.
|
| I personally find that the overlapping bell curve
| illustration obscures that understanding, making it emphasize
| more that a small number of below-average men are still
| taller than some women, and completely hiding the tail of
| outlier men on the left who are shorter than the vast
| majority of women...
|
| Stacked histograms are a better way to visualize this kind of
| faceted distribution - but even that has issues.
| ackfoobar wrote:
| > the area under the male height curve that is not under
| the female one.
|
| It's not obvious to me. Yes the height of the male graph is
| lower, but is spread wider.
|
| > It's just the sum of the excess number of men of a given
| height over and above the number of women of the same
| height.
|
| It's simply that the female histogram covers part of the
| male histogram. It's a bit confusing. If I make the graph I
| will colour the overlapped parts a different colour.
|
| This is not a problem when we show only the bell curves.
| RcouF1uZ4gsC wrote:
| > Once you reached 20, your life expectancy was a bit lower
| than today, but it was common for people to reach 60.
|
| If you were a man. If you were a woman, there was still the
| high risk of maternal mortality. Add to that the large number
| of births, and a significant amount of women died during
| pregnancy/birth/post-birth.
| elephant_burger wrote:
| To your point, the global "average" life expectancy since the
| 1700s to today visualized
| https://ourworldindata.org/grapher/life-expectancy?tab=chart...
| bigDinosaur wrote:
| How to mislead with data 101!
| jwlit wrote:
| Indeed, though see the article linked at the bottom of that
| one, which goes into more of the nuance and has
| distribution curves etc: https://ourworldindata.org/life-
| expectancy-how-is-it-calcula...
| kqr wrote:
| Our World In Data has a plot of conditional life expectancy
| throughout recent history. It's one of my favourite plots of
| all time not because it's important, but informative and
| intuitive.
|
| https://ourworldindata.org/uploads/2013/05/Life-expectancy-b...
| WanderPanda wrote:
| Nice plot, we should work on steepening those curves to a
| slope of greater than one
| xeromal wrote:
| Is that drop in the earlier 1900s localized to the young the
| spanish flu?
| cm2187 wrote:
| That's a very interesting plot thank you.
|
| Another very powerful demographic chart that I lost (in case
| someone knows where it is) is a 3 dimensional chart. Y axis
| is children per women, X axis is infant mortality, and then
| there is a slider to look at the evolution through time. All
| countries are plotted as points.
|
| The reason it is powerful is because by moving the slider you
| can see the evolution through time. For most now developed
| countries, infant mortality and children per women both
| reduced simultaneously as the progress of medicine and the
| evolution of society have been very gradual. But african
| countries are following a different path, where the infant
| mortality collapsed but is not followed by a reduction of
| children per woman (only a few countries have started to take
| that turn). That is basically all you need to know to explain
| the major demographic shift we are about to observe in
| Africa.
| kqr wrote:
| Also Our World in Data:
| https://ourworldindata.org/grapher/fertility-vs-child-
| mortal...
| cm2187 wrote:
| It's exactly that, thank you. The version I saw didn't
| change the scale when you move the slider which makes it
| easier to see what is going on, but I am pretty sure it
| must be earlier version of that chart.
| wardedVibe wrote:
| The Spanish fly/great war dip is staggering
| smcl wrote:
| And the sharp increase around the mid 1940s is quite
| remarkable too. I was wondering what caused that, I guess
| the polio vaccination started getting rolled out but I
| don't if it was that big of a cause of death.
| kqr wrote:
| "Methods for mass production of penicillin were patented
| by Andrew Jackson Moyer in 1945."
|
| Antibiotics are a lifesaver to reckon with.
| smcl wrote:
| Ahhh of course :D
| Zenst wrote:
| Issue I have with averages is they never say how worked out as
| often they will use a method that suits the outcome they wish.
| You get different results from mode, medium and mean averages
| and can cherry pick wich one fits the narrative and use that
| with the label `average` and it's just accepted by the
| majority.
|
| Personaly ALL averages should list all three averages for
| context and clarity as they do offer a greater insight.
| stepanhruda wrote:
| Is this actually very common? "average" is the common word
| for "mean", I haven't seen anyone to present median or mode
| as an average.
| Zenst wrote:
| That's the problem as mean can be skewed and sure it is
| often the go to use for averages but can slant the data.
|
| example:
|
| data 1, 2, 2, 2, 10
|
| Mean: 3.4 Median: 2 Mode: 2
|
| Nice online tool to easily work these out
| https://www.calculator.net/mean-median-mode-range-
| calculator...
| kqr wrote:
| Depending on the purpose of finding a central tendency of
| those numbers, I would argue the mean is correct and the
| others are skewed...
| Zenst wrote:
| I was always bemused that the average family size was 2.4
| children as no family fits that average ever. With mode
| and medium that would not happen.
|
| Of note I have no idea what the average family size is
| children wise, just going on longstanding data from UK
| that in itself may be out of date, though does highlight
| the point.
|
| [EDIT fixed typo]
| kqr wrote:
| Yet if we set up a game with a penalty proportional to
| the distance between your guess and the true number of
| children for a family, and you guess the median or mode,
| you'll be right more often than I (because I will never
| be right), but you will also continually be losing money
| to my guess of the mean.
|
| What matters in real life is generally not how often you
| are correct, but rather by how much you are wrong. What
| you need to minimise is not your error rate, but the
| consequences when you are wrong. You are free to make an
| infinite amount of mistakes, as long as you are sure to
| make them in such a way that they are comparatively
| insignificant.
| Zenst wrote:
| > Yet if we set up a game with a penalty proportional to
| the distance between your guess and the true number of
| children for a family, and you guess the median or mode,
| you'll be right more often than I (because I will never
| be right), but you will also continually be losing money
| to my guess of the mean.
|
| Not sure were you went there, but the point is that you
| can overdetail in a way that abstracts from reality.
| stepanhruda wrote:
| Yes, it can be a problem and I agree more context like
| median or a full histogram should be more common, but I
| have never seen anyone claim that the average was 2 in
| your example.
| texaslonghorn5 wrote:
| While the average value was 3.4, I don't think it would
| be unfair to suggest the average person would have scored
| a 2 (or whatever the relevant scenario is).
| kqr wrote:
| It depends on your definition of "very common" of course,
| but I have come across people using "average" to mean both
| "typical" and "most common" and "middle of the range" and
| "my preference" and a whole slew of other things.
| jarenmf wrote:
| Indeed, I keep hearing this countless times. People genuinely
| think that people died in their 30s two centuries ago.
| wizofaus wrote:
| Pretty sure it was a good deal more common to do so than it
| is now.
| olddustytrail wrote:
| They did. Large numbers of them. Often in childbirth.
| inglor_cz wrote:
| People don't generally understand premodern demography. We have
| fairly good demographic record of England, where detailed birth
| and death records were kept.
|
| As of the 18th century, about 30 per cent of people died before
| reaching adulthood, but this percentage seems to be much higher
| in urban areas, which acted like population sinks. (Pathogens
| were really concentrated there.) Once you lived to be 20, you
| had more than even chance to live to 40, and a good (AFAIK over
| 35 per cent) chance to live to 60, but the drop-off after that
| was steep, 70 y.o.s were already uncommon and 80 y.o.s very
| rare.
|
| Interestingly, cardinals and popes lived significantly longer,
| 70-somethings were a common sight in conclaves. Easier life, no
| military threat, good water, almost no risk of famines.
|
| I am writing this from the top of my head, so precise values
| may differ from my handwaving. But I believe that the values
| are roughly correct.
| atwood22 wrote:
| Hmm based on your comment, I think people understand better
| than you think. Obviously if the life expectancy is 40, then
| some people live longer. Half of all people who live to 20
| dying before 40 is probably what most people think of when
| they think about a 40 year life expectancy.
| Amezarak wrote:
| I don't know specifically about that time period, but there
| have been dips and peaks in life expectancy over time. In
| the latter half of the 19th century in England, life
| expectancy at adulthood was the same or better than it is
| today.
|
| https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672390/
|
| There was actually a major, severe DECLINE after that
| associated with globalization, trade, and further
| industrialization, which is where many charts begin.
|
| Think about how incredible that is - nothing we would
| recognize as modern medicine, but adults living just as
| long. I can't think of any greater indictment of our health
| in modern civilization, especially given the amount of
| resources we expend. I mean, just think about - aside from
| the improvements in child mortality which are almost
| entirely just from now nearly century old antibiotics and
| vaccines technology, we spend 20% of our GDP to achieve the
| same results as the 1850s English who got them for next to
| nothing in comparison. Progress!
| Darmody wrote:
| From my experience, people think most people back then
| lived around 40 years, while some lived less and some lived
| more.
| elephant_burger wrote:
| Looking at deaths globally by age as a distribution shows how
| the average can mislead https://www.google.com/search?q=death
| s+globally+by+age&rlz=1...
| pxmpxm wrote:
| IIRC bulk of the gain in average life expectancy over the
| last 2 centuries came from reducing infant mortality, which
| had outside impact on the aggregate mean.
| Phiwise_ wrote:
| People don't generally understand how statistical metrics are
| supposed to work. The whole point of statistics is to give you
| reasonable expectations for the possibilities of a space that
| is both full of variation but well-explored based on what
| particulars you know already. The problem is that most people
| don't realize the arithmetic mean is intended to give you the
| expectations associated with not knowing essentially anything.
| It's the map you give a stranger in a strange land (am I using
| that reference right? I haven't actually read the book yet);
| the way I explain how to get somewhere in my hometown to a
| family member isn't just not the same as the way I would to
| somewhere near my new job, but runs a worryingly high chance of
| making things less clear than if they just tried to do it
| themselves (well, at least, before the days of google maps. Why
| does technology have to be so good at ruining metaphors?). When
| you have, or will have, information, working without it is just
| asking to get tripped up. This the brilliance of the adjustable
| cockpits example: The Air Force leadership assumed they
| couldn't set cockpits to fit their pilots because they didn't
| currently know which pilot would fly which plane, forgetting
| that no plane takes off in the Air Force without the leadership
| telling a particular pilot to get in a particular plane. Once
| they adopted the life-like "What do I know about Y given what I
| (will) know about X" approach over the card-table-like "What do
| I know about Y given I can't know anything about X", seemingly
| untouchable problems immediately resolved out almost on their
| own.
|
| We see this immediately and intuitively from the great
| conditional graph in this comment:
| https://news.ycombinator.com/item?id=31958102
| nostromo95 wrote:
| >am I using that reference right?
|
| Looks right to me! Although interestingly it's unclear which
| book / Book you're referring to, as the expression comes from
| Exodus 2:22:
|
| "And she bare him a son, and he called his name Gershom: for
| he said, I have been a stranger in a strange land."
| mrwh wrote:
| Another way of looking at it is that's even worse though.
| Today, it's very rare to have to deal with the death of a
| child; then, almost everyone had to go through that. And to
| say, "once you reached" should really be "if you reached".
| secabeen wrote:
| The data point you want to use is the modal age of adult death,
| but everyone is fixed on the mean age of death, which you
| correctly note is completely skewed by childhood mortality.
| melling wrote:
| That's because all probabilities are conditional, and people
| don't consider that.
|
| These two things helped me to understand probability better.
|
| The Signal and the Noise:
|
| https://www.amazon.com/Signal-Noise-Many-Predictions-Fail-bu...
|
| The videos for Harvard Statistics 110:
|
| https://projects.iq.harvard.edu/stat110/home
| lawrenceyan wrote:
| This is a great quote. I might have to steal this.
| _the_inflator wrote:
| Also have a look at Anscombe's Quartet to get literally an
| overview, what averages can mean:
| https://en.wikipedia.org/wiki/Anscombe%27s_quartet
| ThomPete wrote:
| My favorite example of average to illustrate how you can say
| something factually true, but realistically untrue "Humans on
| average have one testicle".
| jimhefferon wrote:
| Another interesting, and very readable, article on the subject is
| _What does the mean really mean?_
| https://arxiv.org/abs/2003.01973
| qalmakka wrote:
| There was this Roman poet, Trilussa, which created a good
| description of why averages are bad, which is known in Italy as
| "Trilussa's Chicken"
|
| Roughly translated, it goes as follows:
|
| "Following the current statistics, it turns out you're expected
| to be able to eat one chicken per year, and, if you can't afford
| it, it goes into the average anyway, because there's someone else
| out there eating two".
| huachimingo wrote:
| It is the same as Nicanor Parra's:
|
| There are two pieces of bread. You eat two. I eat none. Average
| consumption: one bread per person
| HideousKojima wrote:
| The average human has one breast and one testicle (give or take
| a fraction).
| Phiwise_ wrote:
| Rome had a conception of statistics? That's very interesting.
| I'd always been told that it was a relatively new science
| coming from french aristocracy gambling or something.
| mdp2021 wrote:
| Carlo Salustri, artistically signing with the anagram
| Trilussa, died in 1950.
| GavinMcG wrote:
| I too read "Roman" to refer to empire. Maybe because of the
| Latin-sounding single name, or maybe because I'm used to
| identifying people by their nationality rather than their
| city.
| qalmakka wrote:
| Sorry, it's modern Roman, not ancient. Trilussa wrote in
| Romanesco, which is a Central Italian dialect (Tuscan and
| central Italian form a somewhat of a linguistical continuum,
| while southern Italian and northern languages are not
| mutually intelligible).
| inetsee wrote:
| My wife worked on the project to upgrade the C-5 cargo plane's
| cockpit. She's 5 feet 1 inch tall, so she was chosen as the test
| person for the 5% end of the usability range. If she couldn't
| reach or operate a control in the cockpit it was a problem and
| the control had to be redesigned.
| sib wrote:
| My wife is 4'10" and often has trouble finding cars in which
| the driver's seat can be adjusted to fit her... I'm guessing
| she's well below the 5th percentile (at least in the US).
| swader999 wrote:
| I hope she doesn't have really long arms.
| Hellbanevil wrote:
| tomohawk wrote:
| This also comes into play with the current discussion of EVs.
| People will say, "you don't need that 500 miles of range." Or,
| "just plug the EV in at night - you don't have to wait at the
| charger."
|
| That probably works well for _average_ use cases, but not for the
| outliers.
|
| The great thing about ICE vehicles is you generally don't have to
| worry about non-average use cases. To reach parity, EVs will need
| to be chargable in 5 minutes from empty to achieve 500 miles of
| range, at 5 degrees F, with 5 year old batteries. If you live in
| California, that may seem like an extreme use case, but it's
| pretty normal around here.
| Andys wrote:
| I thought this until I looked at the histogram of private car
| trip lengths. The vast majority of trips are very short. Its
| unlikely they're all being done on the same day.
| tomohawk wrote:
| Next time you have to bug out because there's a hurricane
| coming, and it's after your commute, so you haven't had time
| to charge the car, are you going to be regretting your
| choice? It's 95F out, humid, and your car AC is going full
| bore as you creep along in traffic to get out of the area.
|
| Yes, that is not an average situation, but there's a lot of
| peace of mind not having to think about it at all. By the
| time I get down to 250 miles in my ICE, I can fill up in 5
| minutes, but still have a very comfortable margin for
| anything that may happen.
|
| And, worst case, if I run out of gas (never happened in my
| lifetime)? I can get a gallon of fuel and drive away. How
| does that work with an EV?
| k__ wrote:
| Sounds like a very US specific problem to me.
| seansmccullough wrote:
| A reasonable US-specific problem. EV limitations like
| this are are why millions of people aren't currently
| interested in buying EVs. Compared to ICE, and EV car is
| more expensive, and essentially has the "road trip"
| feature removed.
| ajconway wrote:
| Alternatively, the charging infrastructure needs to evolve.
| Even considering the currently available technology, imagine
| having 150kW chargers in place of every gas station that we
| have right now. Install ~20 chargers in the most busy
| locations, and the average time spent at the station will no be
| much higher than getting gas.
| formerly_proven wrote:
| Frankly I do not want to share streets with people who drive
| 800 km, refuel and drive even more after that in one go.
| qikInNdOutReply wrote:
| jmillikin wrote:
| There's a joke that goes something like "To an American 200
| years is a long time, to a European 200km is a long
| distance".
|
| Driving from San Diego to Sacramento is about 800km; in good
| weather and light traffic you could cover that in 7 or 8
| hours. Get up early, drive that first leg, stop for lunch,
| then keep going (e.g. towards Portland or Seattle).
|
| Of course, an American would usually stop for gas before
| hitting empty because we're used to the idea of "No food or
| fuel next 2 hours".
| jfk13 wrote:
| A couple of decades ago, when I was young(er) and (more)
| foolish, I several times did the drive between Columbia, SC
| and Dallas, TX in a single day. It was just a touch over a
| thousand miles. Idiocy.
| k__ wrote:
| My grandfather drove us to holiday from Germany to Spain
| every year.
|
| Took 2-3 days. He slept a few hours in the car at night.
| h2odragon wrote:
| I once did a whirlwind trip from TN to NM, UT, CO, and
| back to TN. 5,000+ miles in 5 days. Average speed over
| 40MPH _with_ some sleep and some meetings included.
| Idiocy, indeed.
| ghaff wrote:
| 7 or 8 hours is a pretty long day driving for one person.
| But people do switch off and, even in New England where
| distances tend to be shorter, a 5 hour drive up to
| somewhere like Maine is hardly exceptional.
| pfortuny wrote:
| There are people who alternate. Married couples, friends,
| whatever. Happens a lot.
| namdnay wrote:
| I think the main mistake as concerns EVS (and many other
| environmental questions) is the belief that tomorrow will have
| exactly the same comforts as yesterday. If having to wait 45mn
| every 400km is the biggest price you're paying for the carbon
| transition, you're very lucky
| gonzo41 wrote:
| If the EV market could agree on a battery size and
| configuration, then maybe doing a full swap of a battery could
| be done like an f1 Pitstop.
|
| Similar to those electric scooters in Asia, Just imagine if you
| rolled over a pitstop and had the battery quicky taken out from
| below the car and then a new battery placed back in.
|
| That sort of system could change the economics of building an
| ev as you could move to a model where users don't really own
| the battery they rent it for a while until they need a swap.
|
| Or electric cargo bicycles. Because every bike on the road is
| one less massive car.
| cguess wrote:
| Battery degradation would limit expectations. "Oh shit, I got
| one of those old batteries that will only get me 150 miles
| when I was hoping for 200 to get to my mother-in-law's for
| Thanksgiving" isn't going to work.
| carlhjerpe wrote:
| Could be solved by measuring how much charge it takes and
| bills you for that + some min charge for the change service
| would be the price, a bit more complex but I reckon the
| swap service could be made simple enough that it's low
| cost.
| ljosifov wrote:
| Then you are going to drive 150 miles and spend extra 3
| mins to change the battery again - no? Not a big deal, and
| certainly not a deal breaker. Nah - the pit-stop type
| battery replacement is the obvious solution to most EV
| charging problems, but we humans can not execute it. It
| requires level of coordination and cooperation between
| companies that we are not easily capable of right now.
| bluGill wrote:
| Battery replacement works only if you make compromises.
| EVs are currently designed to put batteries where they
| fit, a standard battery means much less batteries and
| thus much less range. Second cars come in different
| sizes, a swappable battery needs to fit in the smallest
| car, leaving larger cars with a much to small battery.
|
| Sure it can work, but overall I have to call it a bad
| compromise.
| PaulRobinson wrote:
| You're making the mistake of average use cases.
|
| Your first idea requires new, expensive infrastructure that
| will need maintenance due to mechanical parts. Given charging
| points are regularly broken at the moment, I don't have high
| hopes. But even if we overcame that: it's impractical in
| almost every major city in the World, because you'd have to
| drastically alter existing spaces, such as filling stations.
|
| This might work in your context, and many others. It might
| even work for the "average" use case. But for 75% of the
| developed World (where the EV market is the fastest growing),
| I'm not convinced.
|
| And the electric cargo bike argument - or bikes in general -
| work great for the "average" journey, but not many people
| actually take that journey.
|
| My most frequent drive is 200+ miles in normally wet or cold
| weather. My next most frequent is 15+ miles in baking hot
| Summer sunshine in a heavily congested city where I need
| aircon. Neither would be pleasant on a bike - electric or
| not.
|
| And I think that's the point of this discussion: engineering
| for averages is a terrible idea, and most EVs don't work for
| most journey profiles for most of the World's drivers today,
| compared to ICE
| giaour wrote:
| There was an Israeli startup that tried this out ~10 years
| ago: https://jalopnik.com/battery-swapping-israeli-startup-
| better...
|
| One problem was that they had chosen one model of car to
| simplify battery inventory, but the car was not a good fit
| for their initial markets.
| nradov wrote:
| Nio is doing battery swapping successfully with their EVs in
| China.
|
| https://www.nio.com/blog/current-state-ev-battery-swapping
| Hellbanevil wrote:
| spoonjim wrote:
| I don't think this will ever happen. You will need to
| inventory $30,000 parts to sell them for $30,005 (if $5 is
| the cost of the charge). And the cars will have to have tons
| of design compromises.
| CogitoCogito wrote:
| EVs don't need to entirely displace ICEs. Many zealots think
| so, but it isn't even necessary from an environmental
| perspective.
|
| But I think the main complication comes to ownership. Are you
| going to own an EV and an ICE? Or are you doing to own and EV
| and rent an ICE when needed? Or the other way around? And even
| if you rent it can become complicated. Last weekend I rented a
| car and it needed to be an EV since I booked it late and that's
| all that was late. I personally would rather not have dealt
| with the extra complexity of charging it compared to just
| putting gas in the tank.
|
| But really I thin the issue is that if we move to EVs it kind
| of forces some sort of vehicle specialization where it
| previously didn't feel as necessary. That opens a big can of
| worms when it comes to changes in lifestyle for many people.
| ghaff wrote:
| In general, people often don't optimize for their average use
| case like commuting or going to the grocery store. They
| optimize for weekend recreation, buying lumber, the
| occasional long drive off the beaten path, etc. Some of it
| isn't entirely rational. But it's also the case that, for
| many of us, renting a car is a bit of a pain and it's often
| hard to depend on renting a more specialized vehicle if you
| need one. So if you're just going to own one vehicle, you
| tend to buy one for the 10-20% case, not the 80% case.
| jdasdf wrote:
| >EVs don't need to entirely displace ICEs.
|
| They do when ICEs are getting banned.
| AnIdiotOnTheNet wrote:
| You know what else is going to open a big can of worms when
| it comes to changes in lifestyle for many people? Climate
| change.
| bluGill wrote:
| I'm surprised you can rent an EV. Few hotels have a place to
| charge them, so there goes the idea of plugging them in
| overnight, which is the main advantage of EVs
| zoover2020 wrote:
| In the US maybe. Lot's of countries which offer charge
| capabilities for EVs everywhere, even at hotels (The
| Netherlands, Norway etc.).
| hef19898 wrote:
| I've even seen fast chargers at petrol stations in Tunsia
| this year, all the way down in the South not to far from
| the Lybian border.
| chrisseaton wrote:
| You can go to a normal super-charger while you have
| breakfast or whatever.
| ngc248 wrote:
| "If bill gates gets on a bus, on an average everyone in the bus
| is a billionaire". Read this somewhere and this made me
| understand why just the average on its own does not say anything.
| texaslonghorn5 wrote:
| I would agree that on average each bus rider has a billion
| dollars, but I can't find away to justify that each person is a
| billionaire on average. Maybe it is because money is continuous
| whereas billionaire status is binary, so averaging it out
| doesn't really make sense.
| Helithumper wrote:
| If you ever check the average, always make sure to _at least_ add
| in the median. I don't know if there's any special syntax for
| this with symbols or whatever but having the median,average,and
| possibly even n together is way better than just the average.
| bigmattystyles wrote:
| This reveals itself with the Carlin joke about the average person
| being dumb and that by implication 1/2 of the population is even
| dumber. Carlin and people who eagerly repeat it don't know about
| distributions and that intelligence is not a standard
| distribution. Mea culpa, I used to parrot and believe the joke...
| samatman wrote:
| Intelligence, as measured, shows a normal distribution. Just
| like height, grip strength, BMI, and many other human metrics.
|
| Hence the name of a rather notorious book by Charles Murray.
| hodgesrm wrote:
| I suspect Carlin understood averages and the diversity of
| intelligence better than your comment implies. He probably was
| just having fun with the idea. After all, it _is_ a good joke.
| programmer_dude wrote:
| The median is also an average.
| bigmattystyles wrote:
| Only in a standard distribution right?
| nostromo95 wrote:
| Any symmetrical distribution will have the mean equal the
| median.
| bigmattystyles wrote:
| But that's the definition of a standard distribution?
| Intelligence is not, at least I think.
| nostromo95 wrote:
| AFAIK "standard distribution" is not a defined
| mathematical term; usually it's shorthand for standard
| normal distribution.
|
| Can't comment on intelligence distributions.
| ackfoobar wrote:
| "standard normal distribution" is a normal distribution
| with mean 0 and s.d. 1.
|
| To talk about whether intelligence follows a (one-
| dimensional) normal distribution we have to assign a
| number to it. That number is usually IQ, but by design
| the raw score is transformed to make IQ scores follow a
| normal distribution.
|
| So it is trivially true.
|
| If we want to go beyond that, what does it even mean to
| say, for example, "twice as smart"?
| ackfoobar wrote:
| Not exactly. This pathological distribution has no mean.
| https://en.wikipedia.org/wiki/Cauchy_distribution
| programmer_dude wrote:
| No, the word average is a place holder for measures of
| central tendencies (like mean, median and mode).
| robg wrote:
| Probability and statistics should have already replaced algebra
| and calculus in modern education. People are just really bad at
| understanding variance and the impacts on what we think we know.
| programmer_dude wrote:
| This is just foolhardy. These things can be and are taught side
| by side in many parts of the world.
| BurningFrog wrote:
| My gut feeling is that the education sector is extremely
| conservative and keeps teaching whatever is has always teached.
|
| This is one argument for homeschooling, I guess.
| solardev wrote:
| Anecdata (I wanted to be a teacher earlier on until I
| actually met a few and heard their stories):
|
| Teachers are generally pretty progressive (both in the
| political and innovation senses), but the legislation (like
| Common Core), state & district educational standards, and
| school boards move more slowly. And in the US, the primary
| schools are largely funded and overseen by local parents
| (municipal and state), so the school priorities and cultures
| partially reflect local priorities.
|
| There's often debate between what individual teachers want to
| teach (a product of their individual preferences and
| backgrounds and values) vs what the administration forces
| them to teach (as a reflection of the political and business
| realities of their particular school). There's often a
| personality difference between the two classes too (educators
| vs admin types), with the former often being (at a
| stereotype) starry-eyed idealists and the latter being
| grounded management types with an eye on the numbers of
| finance and politics; on top of that, there is also often a
| labor vs mgmt (not quite "owners") divide, with individual
| teachers being pretty much powerless to teachers' unions
| being really strong in some districts. Long story short,
| teachers can't unilaterally change the curricula they teach.
|
| The power struggles affect everything from math (new math,
| math wars, whether to test it, etc.) to social studies (CRT,
| Native studies, bilingualism, religious studies) to science
| (evolution, climate) to business needs (cursive vs typing,
| algorithms or letterheads), etc.
|
| Far from being a settled matter, our educational system is
| heavily political and its lack of progress is probably
| reflective of our divisiveness as a country, where two broad
| sides keep playing tug-of-war and veering towards the
| extremes, making tiny gains and losses back and forth.
|
| The kids end up caught in the crossfire. The US, for all the
| money we pour into education, ends up rather poorly educating
| its children vs other developed nations: https://en.wikipedia
| .org/wiki/Programme_for_International_St...
| BurningFrog wrote:
| If parents are a big influence, I'm not surprised if
| schools end up teaching about the same things the parents
| were taught.
| acjohnson55 wrote:
| You need algebra and calculations calculus to do anything
| theoretical in probability. But I'm a fan of working backwards
| from interesting applications of algebra to the fundamentals.
| lkrubner wrote:
| To bring up an issue relevant to Google and tech, this was my
| main criticism James Damore, and why I thought Google had grounds
| to fire him. The First Amendment gives him the right to write an
| incel-inspired manifesto if he wants to, but the misuse of
| "average" for political purposes makes him look like an idiot and
| discredits other work he might do. In his manifesto he argued
| that the average male is better suited to computer programming
| than the average female. How is that in any way relevant at
| Google, which only hires people 4 or 5 or 6 standard deviations
| away from the norm? Average isn't relevant. Bringing up the
| average in situations where the average is not relevant is a
| common mistake, but it is also a very stupid mistake.
|
| https://www.vox.com/identities/2017/8/8/16106728/google-fire...
| JackFr wrote:
| > Google, which only hires people 4 or 5 or 6 standard
| deviations away from the norm?
|
| Puh-lease
| [deleted]
| dnissley wrote:
| > How is that in any way relevant at Google
|
| Because certain people constantly use the fact that there isn't
| 50/50 gender representation in engineering roles as a way to
| imply the profession is particularly sexist. It was absolutely
| relevant to the conversation at hand around "women in stem".
| 6thaccount wrote:
| mojzu wrote:
| Even without the standard deviations I think averages are an
| often abused tool. If you take any statement following the
| lines of "group X is better at task then group Y on average",
| while it might help you win in the long term in a betting
| scenario it doesn't actually provide any information on whether
| any individual from group X is better at the task then any
| individual from group Y
| whatshisface wrote:
| > _In his manifesto he argued that the average male is better
| suited to computer programming than the average female._
|
| That's not what I remember it saying. Are you sure you're
| remembering it right?
| dharmaturtle wrote:
| > Women, on average, have more:
|
| > Openness directed towards feelings and aesthetics rather
| than ideas. Women generally also have a stronger interest in
| people rather than things, relative to men (also interpreted
| as empathizing vs. systemizing).
|
| > These two differences in part explain why women relatively
| prefer jobs in social or artistic areas. More men may like
| coding because it requires systemizing and even within SWEs,
| comparatively more women work on front end, which deals with
| both people and aesthetics.
|
| https://gizmodo.com/exclusive-heres-the-full-10-page-anti-
| di...
| cosmojg wrote:
| I find that I want the median or the mode far more often than I
| want the mean. I don't understand why the latter has subsumed the
| former. I guess it's easier to calculate?
| t_mann wrote:
| This is a poor analogy - usage statistics tend to not follow
| Gaussian distributions, hence the average can be a poor measure
| of central tendency. Body measurements usually don't have that
| problem, and I suppose that the average was actually used as the
| 'starting point', from where pilots could customize. For other
| distributions, one might actually prefer to opt for a different
| statistic altogether.
| martincmartin wrote:
| Average is great when you really care about the total, and want
| the total expressed per thing. For example, if you make 100
| investments, the average return is just a way of talking about
| the total return on all your investments, expressed per
| investment.
|
| For other uses, it can be very misleading.
| lbriner wrote:
| Why does this article not even once mention that average could
| mean "mean", "median" and/or "mode"? Even the title alludes to
| one of the biggest problems in the domain and that is that many
| people don't even realise that there is more than one way to
| measure an average.
|
| There are plenty of examples of where the mean is not
| representative of the sample and where mode or median would be
| more realistic, particularly where some large outliers in a
| relatively small sample would skew the mean.
| kibwen wrote:
| Likely the same reason that when someone says "mean", they
| never bother to specify whether they're referring to the
| arithmetic mean, the geometric mean, or the harmonic mean. :P
| happyopossum wrote:
| Because for the purposes of the article, it just doesn't
| matter. The point is to stop distilling data down to a single
| point, regardless of what math term you want to use.
| asperous wrote:
| I think because the moral of the story is the same, which is
| the airforce switched to customizable controls to support the
| range instead of over focusing on a single "average".
| hamilyon2 wrote:
| And yet, 70 years afterwards, all we have is average ratings of
| everything, from tv shows to restaurants. Not to mention
| inflation, any kind of prices dynamics and wages.
| rahimnathwani wrote:
| "all we have is average ratings of everything, from tv shows"
|
| IIRC IMDB shows mean ratings, but Rotten Tomatoes shows the %
| of ratings above a certain threshold. I find the latter more
| useful.
| sib wrote:
| And Amazon shows the distribution from 1..5 stars, rather than
| just an average (I know, plenty of noise/garbage in there
| still...)
| [deleted]
| toss1 wrote:
| Yup, and the most common usage is product ratings on Amazon,
| which I find a complete waste of time, even before they became
| corrupted by massive rating-spamming. The metric I find useful
| is the ratio of negative (1-2 star) reviews to positive, in the
| product category (some categories seem to have higher usage
| failure rates, or POd users or something).
|
| The average is a waste of time
| jotm wrote:
| It's still possible to get somewhat of an accurate
| understanding of what you're buying if you _read_ some
| reviews.
|
| I read ~10 two star reviews, ~10 four star reviews, much more
| depending on price. One stars tend to be full of stuff like
| "product hasn't arrived", "garboage", user errors. Five stars
| are plagued by spam and paid reviews, and also a lack of
| details. Three stars seem to be split between very picky
| buyers (esp. hate the "I paid $3.50 for this and it's not the
| omega particle!") and people afraid to leave lower ratings
| for reasons.
| toss1 wrote:
| Agree for sure, and some good notes there! (My comment was
| merely limited to scope of the averages issue.)
|
| Definitely must read a decent sampling to see if there's a
| common problem, or it's mostly just malcontents, delivery
| issues, or misunderstanding the product or instructions, or
| just random issues. I've found in doing this that I'm
| usually surprised on the good side.
| kqr wrote:
| The other common misuse of averages I keep hearing confusing "the
| average X" with "the X of the average Y". (Known formally as
| Jensen's inequality.)
|
| So for example, the average time to review a code change is not
| the same as the time it takes to review a code change of average
| size.
|
| The average user experience of a website is not given by the user
| experience of the average response time.
|
| And so on. People tend to compute the average of an easier
| variable and then forget that the derived value of interest is
| often nonlinear in the easier variable.
| hackernewds wrote:
| very interesting. what is the suggested correct way then?
| kqr wrote:
| Draw a random sample of easy variables from the underlying
| distribution, compute the variable of interest on all of
| those, _then_ average.
| blt wrote:
| Nit: Jensen's inequality only applies when the "derived value
| of interest" is a convex function of the "easier variable".
| AdrianB1 wrote:
| The article is a short, low quality version of the previous
| several ones that were explaining in detail the history, the
| changes, the results. It does not belong here.
| leoc wrote:
| Yes, compared to Todd Rose's own article telling the story
| https://www.thestar.com/news/insight/2016/01/16/when-us-air-...
| this feels like a bland summary. Mind you, even Rose's version
| waters things down quite a bit:
| https://news.ycombinator.com/item?id=31961179 .
| vivegi wrote:
| Average by itself doesn't tell much. Average and standard
| deviation computed over multiple samples from the population
| tells a lot.
|
| Learning about the various types of standard control charts is
| quite useful for data-based decision making and monitoring the
| health of a process.
|
| Control charts and Pareto chart of root causes of defects are two
| of the basic tools one needs to establish 'basic stability' in a
| process. Basic stability is a requirement before working on
| improving a process.
| [deleted]
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