by Matt Parker
1 Ironically, about the only fraction binary can store neatly is ½. In base-10 this is 0.5 because five is half of ten and, likewise, in base-2 binary it is 0.1 because one is half of two. And if there were infinitely many digits in 0.01111111 … it would exactly equal 0.1 in the same way 0.99999 … = 1. Ignore people online complaining that 0.99999 … ≠ 1, because they’re all wrong.
2 The number 754 is not significant; the IEEE just number their standards sequentially in the order they were requested. Right before this one was 753: ‘Functional Methods and Equipment for Measuring the Performance of Dial-Pulse (DP) Address Signaling Systems’ and, just after it, 755: ‘Trial-use Extending High Level Language Implementations for Microprocessors’.
Seven: Probably Wrong
1 Almost. The ‘inner’ cycle does not reverse with double dice, but the red-versus-green match-up equalizes to 49 per cent (slightly in green’s favour). There is a second version of Grime Dice which fixes this problem so it stays in red’s favour, but this loses subsets of dice, which function as smaller, non-transitive sets.
Nine: A Round-about Way
1 This carefully calculated figure is surprisingly close to merely assuming that each of the three thousand transactions per working day over twenty-two months took 0.00045 off the index on average.
2 I haven’t just split the difference between the two dates; this is the prediction from a line-of-best-fit of all records between the 6 July 1912 record of 10.6 seconds and the 20 June 1936 record of 10.2 seconds.
3 Yes, these are physics problems with this theory. Maybe one day the regulations for wind assistance will also apply to Brownian motion.
9.49: Too Small to Notice
1 Of course, if you start with a solid block of Swiss cheese and slice it, the holes will line up because they were formed by bubbles in the cheese. So assume the Swiss cheese slices have been adequately shuffled.
2 This is the opposite to what we saw with the Apollo fire, where the only exit was a plug seal. Emergency exits should never be plug seals. In this case, the windscreen should never need to open so could be fitted from the inside.
Ten: Units, Conventions, and Why Can’t We All Just Get Along?
1 Units involving feet, pounds, and so on, used in the US are ‘United States customary units’ or ‘English Engineering Units’, not imperial units. But I’ll use ‘imperial units’ as a catch-all for these families of units.
Eleven: Stats the Way I Like It
1 The ‘crack team’ was actually a bunch of students looking for extra work, and the tour had to be scheduled around when they had time off from classes. The air force tried to get an academic anthropological department from a university involved, but no one was interested.
2 The extra sets of data were made by slowly evolving the data via tiny changes which moved the data points towards a new picture but didn’t change the averages and standard deviations. The software to do this has been made freely available.
3 Their study was finally published thirteen years later, in 1993, as an example of publication bias.
4 In the interest of full disclosure, this is before I was writing for the Guardian myself, but the article was written by my friend Ben Goldacre, of AllTrials fame.
Twelve: Tltloay Rodanm
1 At the time of writing, ERNIE is no longer on public display at the Science Museum.
2 It pleases me greatly that part of the required word count of my book has now officially been randomly generated.
3 This was still in the era when the US government controlled the export of software with strong encryption, as they considered such cryptography as munitions. So the ‘international version’ of Netscape used such a small range of cryptographic keys (40-bit compared to the normal 128-bit) that it could routinely be broken in about thirty hours anyway.
Thirteen: Does Not Compute
1 Combined with a different language which ignores spaces, tabs and line breaks, this means it is possible to write bilingual code which can be parsed by two different programming languages.
