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Introduction to QuantLib Development with Luigi Ballabio - London, September 19-21st, 2016 -

Understanding Uncertainty's Blog


Explaining 5-sigma for the Higgs: how well did they do?

July 8, 2012 Comments (0)

Warning, this is for statistical pedants only. To recap, the results on the Higgs are communicated in terms of the numbers of sigmas, which has been calculated by the teams from what is generally (outside the world of CERN) termed a P-value: the probability of observing such an extreme result, were there not really anything going on. 5-sigmas corresponds to around a 1 in 3,500,000 chance. This tiny probability is applied to the data, but the common misinterpretation is to apply it to the...

Higgs: is it one-sided or two-sided?

July 3, 2012 Comments (0)

Announcements about the Higgs Boson are invariably framed in terms of the number of sigmas, with 5-sigmas needed for a ‘discovery’. Media outlets helpfully explain what this means by translating 5-sigmas to a probability, which is almost invariably misreported as a probability of the hypothesis that it is all just statistical error e.g. “meaning that it has just a 0.00006% probability that the result is due to chance” [Nature] (see bottom of this blog for comments about the...

Drinking again

June 1, 2012 Comments (0)

Alcohol can cause very serious problems, both for individuals, their families and society. But the Daily Mail’s story yesterday with the headline “Don't drink more than THREE glasses of wine a week: Oxford study claims slashing the official alcohol limit would save 4,500 lives a year” almost universally aroused derision among its many commenters. I was on World at One (31:27) discussing this Oxford study with one of the authors. I had to whip through the stats quickly so here is more of an...

Meat and dying

March 21, 2012 Comments (0)

After all the recent coverage of the possible harms of red meat, I've done an article explaining how, if we believe the figures, eating quite a lot of extra red meat each week will take, on average, a year off our life.

Cambridge Coincidence Survey

January 13, 2012 Comments (0)

Professor David Spiegelhalter of Cambridge University wants to know about your coincidences! Post your coincidence Read the coincidence stories Why? By recording your coincidence stories here, you can help him build a picture of what kinds of coincidences are out there and which ones seem to ‘get to’ us the most. Your coincidence stories can also help him explore the scientific explanations which may account for them – whether by doing the maths to calculate the chances of a coincidence, or...

Wiped Out

December 17, 2011 Comments (0)

Appearing on Winter Wipeout today. Enough said. Looking deranged at the prospect of the Big Balls Wrote an article for the Times, which appeared as this.

BBC website headline wrong shock horror

December 8, 2011 Comments (0)

Bowel cancer screening 'does cut deaths', said the BBC News website today, in a report on a study using data from the NHS Bowel Cancer Screening Programme in England, published in the magnificently named journal Gut. Wow, I thought, that was quick, the programme has been going only since 2006 and didn't cover the whole country till 2010. Have they really found clear evidence of an effect on death rates already? Well, no, they haven't. The story is a bit more complicated and subtle than the...

Why it’s important to be pedantic about sigmas and commas

December 3, 2011 Comments (0)

The BBC reported last week that evidence for the Higgs Boson is “around the two-sigma level of certainty” and provides further explanation: Particle physics has an accepted definition for a "discovery": a five-sigma level of certainty. The number of standard deviations, or sigmas, is a measure of how unlikely it is that an experimental result is simply down to chance rather than a real effect” This is nice and clear, but also wrong. The number of sigmas does not say 'how unlikely the result...

Are the Brits really fatter than other Europeans?

November 27, 2011 Comments (0)

Lots of press reports in the last couple of days on how UK women are the fattest in Europe, for example in the Daily Mail and on the BBC News website. I'm still in Berlin, and it was in the papers here too. The tabloid-style Berliner Kurier went with the headline "Man, they are fat, man", while the N24 news service went with "British and Maltese are the fattest Europeans". But is it another dodgy league table? Well, yes, though for different reasons from those we've looked at here or here. And...

The next Piccadilly line train is leaving from ....

November 19, 2011 Comments (0)

Kings Cross Station now not only has a platform 9$\frac{3}{4}$, but also a platform 0. And for the numerically challenged, there are repeated announcements that 'customers are advised that Platform 0 is situated next to Platform 1' I suppose the Underground platforms will now have to be given complex numbers. [That is an unofficial entry from the Department of Pure Mathematics and Mathematical Statistics, University of Cambridge, for next year's Round Britain Mathematical Joke competition.]...