You're listening to a more or less podcast from the BBC. For more information about the program,

please go to the website bbc.co.uk slash radio4.

Hello and welcome to more or less your weekly guides to the numbers in the news and in life.

This week they'll be wonderment in medieval Italy. It's impossible for us to realise

the beginning of the 13th century nobody in Europe had ever seen that kind of thing before

and will respond to your friends' it commentary on the mathematics of WOQ tags.

Do keep those emails coming in to more or less at bbc.co.uk whether you love what we're doing,

hate it or just want to ask a question. One loyal listener Robert Matthew has done just that.

It would be good to hear a more or less analysis of the meaning of two, three and five

sigma evidence that's being routinely abused not only by the media reporting the Higgs boson

supposed discovery but also by some physicist themselves. It turns out that Mr. Matthews

had trained physicist and a visiting reader at Aston University. I called him to chat this one

through. When the result was announced at CERN on Tuesday there was talk about two experiments

there finding what they described as two sigma evidence for the existence of the Higgs

and this was often explained in terms of it representing a just five percent chance that the

result was just a fluke. Now this is what more or less listeners might be familiar with the idea

of statistical significance because you're getting at the same concept right? Yes that's right and

it's often banded around as being a measure of the probability that your result is just a fluke.

Now unfortunately he doesn't mean that. What he actually means and here the definition is

something that you need to slightly concentrate for it's the probability of getting at least

as impressive evidence as you actually got on the assumption that fluke with the true explanation.

Now instantly you can see that there's probably an issue with simply flipping that figure around

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