May 12, 2013 Leave a comment
More people live inside this area than live outside:
You might also like this graphic of population density.
Show me the numbers
January 8, 2013 2 Comments
Over 98% of expert games begin with 1 of 4 moves, out of a possible 20:
I used to play the Grob (1.g4) and did quite well with it. It’s a trade off, making a slightly less good first move to very quickly get into positions that your opponent has never been in before and needs to use up clock time to consider options from an unusually early stage of the game.
This is a tactic that Kasparov used against IBM’s Deep Blue, reaching a position after 3 moves that had only ever been seen once before at tournament level.
in any long game of chess it’s quite likely that a position is reached that no two players in the history of humanity have encountered before.
More in Nate Silver’s ‘The Signal and the Noise’.
November 17, 2012 2 Comments
I attended a lecture this week on research between stress and heart attacks, where this chart (from a New England Journal of Medicine paper) was displayed, showing incidences of heart attacks in the German population over the period of the 2006 Football World Cup, along with the data for previous years for comparison:
October 27, 2012 1 Comment
In an article by Tim Harford, it was reported that only 25% of Labour MPs were able to correctly answer the question “what is the probability of getting two heads when a coin is tossed twice?”
For comparison, 30% of the general population got the question right.
October 24, 2012 1 Comment
Today I went to a ‘bite-sized lunchtime lecture’ at UCL, and courtesy of Dr Sara Hillman learnt that a low birth weight child was a predictor of future diabetes in the father, and that in turn having a father who smoked was a predictor of the baby being born with a low birth weight.
And then across the road at the Wellcome Trust had a look at a set of books mapping all 23 chromosomes containing the complete human DNA sequence:
There are 3 billion letters in the books, and if you compared your own DNA to the sample in the book you’d find only a few million differences
August 7, 2012 Leave a comment
Today’s 16-yr-old age group world record holder would have won a bronze medal in the 1980 100m Olympics.
Here’s a graph from the New York Times showing how far other Olympic medal winners would be behind Usain Bolt at the finish line of the 100m:
May 3, 2012 3 Comments
I was wondering why the London-based taxi firm, Addison Lee, had so many bad reviews all of a sudden on its iPhone app and so did a little googling. This Guardian article explains part of the controversy*, which concerns a quote by the company’s chairman:
“There has, as we all know, been a tremendous upsurge in cycling … These cyclists are throwing themselves onto some of the most congested spaces in the world … the influx of beginner cyclists is going to lead to an overall increase in accidents involving cyclists.
“The rest of us occupying this road space have had to undergo extensive training.
“It is time for us to say to cyclists, ‘You want to join our gang, get trained….”
The Guardian felt differently however, using as evidence the fact that motorists are responsible for up to 75% of collisions involving cyclists. Their source was an earlier Guardian article which contained this:
The data, which was analysed by the Transport Research Laboratory (TRL) …found that police attributed responsibility for collisions to … the driver solely in about 60%-75% of all cases, [with] riders solely at fault 17%-25% of the time … CTC said the report showed that the government needed to focus more on driver behaviour …”We believe this report strongly supports our view that the biggest problem for cyclists is bad driving.”
I don’t agree that the data supports that the view that the government should concentrate on driers [though this may be true]. The statistics reported relate to the probability that party x caused an accident given that an accident occurred. It can often be useful to analyse something with extreme numbers, so let’s do that.
Imagine there are 1,000,000 motorists, just 4 cyclists, and 3 collisions. Two of the collisions are the fault of the driver, and one is down to the cyclist. So 66% of accidents are caused by motorists, but this ignores the fact that there are relatively more drivers than cyclists (ok, a lot more given the numbers we picked). The bigger picture is that in this version of London a mere 1 in 500,000 motorists cause accidents, as opposed to a massive 1 in 4 cyclists.**
A related stat I remember: you have the same chance of dying on a 200-mile motorbike ride in the UK as you do of getting killed whilst serving for a single day in the British army in Afghanistan (a year or so ago).
* The actual source of bad reviews seems more likely to be by black cab drivers not taking kindly to their unique privilege of being able to use bus lanes being challenged – a challenge which I think has some merit.
**When I first heard about Monty and his 3 doors I didn’t guess to change door, so happy to receive a challenge on this way of looking at the stats…
April 12, 2012 Leave a comment
As an ex-physicist who realises later in life that he’d probably rather have studied economics, I’d like to paraphrase from an interesting article by Tom Murphy. It uses fundamental physics to argue that economic growth cannot continue indefinitely, albeit under the assumption that increases in GDP require an increased use of energy*:
US energy consumption has increased by about 3% per year for several centuries.This is partly due to increases in population, but per-capita energy use itself has grown also — our energy lives today are far richer than those of our great-great-grandparents a century ago.
So even if population stabilizes, it’s fair to say we are accustomed to per-capita energy growth.
The Earth has only one mechanism for releasing heat to space, and that’s via infrared radiation. It’s well understood. If we use more energy (it must all end up as heat energy) then more must be radiated away, and the surface temperature of the planet will increase.
This graph, which presumes a constant 2.3% energy increase per year, plots the Earth’s surface temperature over time:
The upshot is that at a 2.3% growth rate, the Earth would reach boiling temperature in about 400 years. This statement is independent of technology. Even if we don’t have a name for the energy source yet, as long as it obeys the laws of thermodynamics, we cook ourselves with perpetual energy increase. Thermodynamic limits impose a cap to energy growth due to the process of radiating the spent energy away.
*Under a model in which GDP is fixed, with conditions of stable energy, stable population, and steady-state economy, then if we accumulate knowledge, improve the quality of life, and thus create an unambiguously more desirable world this is a form of economic growth, but one which more normally falls under the title of “development” rather than “growth”.
April 8, 2012 2 Comments
I’ve come across this a few times over the years, and been meaning to post it the next time I saw the numbers somewhere. And today I have, here:
In 1800, a candle providing one hour’s light cost six hours’ work. In the 1880s, the same light from a kerosene lamp took 15 minutes’ work to pay for. In 1950, it was eight seconds. Today, it’s half a second. In these terms, we are 43,200 times better off than in 1800.
The 1800 number I think is too high (I reckon you can go and find some wood in less than 6 hrs, or buy some for an amount smaller than 6 hrs of labour). Order of magnitude correct though.
I also think it takes less than half a second, by the way, today, plugging in average salary and electricity kw/h numbers for the UK.
But the thrust of the point is clear, we are massively better off than generations before because we have gotten more efficient at producing things. Four of the basic human needs, food, clothing, fuel, and housing, are now far cheaper in terms of the average wage.
And given it’s Easter, remember, stars died so that you could live.