david's blog

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

Warning, this is for statistical pedants only.

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

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.

Drinking again

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.

Meat and dying

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.

Wiped Out

Appearing on Winter Wipeout today. Enough said.

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Looking deranged at the prospect of the Big Balls

Wrote an article for the Times, which appeared as this.

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

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 it is also wrong, as we have pointed out before in a previous blog by Kevin McConway.

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

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.

The risk of queuing?

Got a short article in the Times today about the UK Border Agency relaxing its checks over the summer.

I wish I had included the following interesting information provided by the excellent Home Office Immigration Statistics April-June 2011. In 2010 there were around 100,000,000 admissions to the UK , and around 19,000 non-asylum individuals were refused entry. That's around 1 in 5000 admissions, about 35 plane-loads.

So someone should be able to estimate how many people were admitted who would otherwise have been refused entry - it may not be very many.

Another doubtful league table?

David Cameron has prominently commented on the recent performance tables concerning adoption in local authorities, in particular the proportion of children whose adoption placement occurs within 12 months. But are the local authorities really as different as they have been made out to be?


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