Skip to main content

Posts

The joy of sigma

Anyone who looks in a bit of detail at scientific results may have come across p-values and sigmas being used to determine the significance of a outcome - but what are they, and why is there a huge disparity between practice in the social sciences and physics? These are statistical measures that determine the probability of the results being obtained if the 'null hypothesis' is true - which is to say if the effect being reported doesn't exist. The social sciences, notably psychology, usually consider the marker for statistical significance to be a p-value of less than 0.05, while in physics the aim is often to have a 5 sigma result. Both these measures depend on creating a probability distribution, showing the likelihood of different values occuring. The p-value is a direct measure of the probability of getting the reported results if the null-hypothesis applies. So, a p-value of 0.05 means there is one in twenty (1/20 = 0.05) chance of this happening. Sigmas effectively me
Recent posts

The Gift of a Radio - Justin Webb ****

This isn't the kind of book I usually read, but it piqued my interest when someone told me about it - and it certainly was worth getting into. If you are a BBC Radio 4 listener (or subscribe to the Americast podcast) you will be familiar with Justin Webb's soothing tones - this memoir of his childhood through to going to university gives a vivid picture of his bizarre upbringing. Webb never met his father (who would become a reasonably well-known BBC reporter), being brought up by his mother and stepfather, each of whom had quite serious problems. His stepfather had a form of mental illness that included paranoia, while his mother was intensely snobbish, insisting on every little social divider that would put a gap between her upper-middle-class-on-hard-times position and anyone she considered socially inferior.  Their home life seems to have consisted mostly of silence, though there was a strong bond between Webb and his mother, arguably an unhealthy one. He was then sent to a

Ghost singers

When I was 13, I sang in a performance of Mahler's third symphony with the Hallé Orchestra under Sir John Barbirolli. Our school's 'special choir' was a regular feature in Manchester performances of orchestral  pieces with children's parts - amongst other outings, I sang in Stravinsky's Persephone , Verdi's Otello , Malcolm Williamson's Our Man in Havana and Mussorgsky's Khovanschina . We performed Mahler 3 a total of three times - concerts in at the Free Trade Hall and the Festival Hall, and a BBC recording for broadcast. But what I didn't realise until a few weeks ago was that the BBC had issued that recording as an album. I managed to get hold of a CD copy and had the eerie experience of hearing myself and fellow choir members from 55 years ago. The (extremely long) symphony was quite a trial of patience for us. We had movement after movement marked 'tacet' on our copies, before featuring in the 4 minutes or so of the movement marked

A PR triumph

I get a lot of press releases, but I have enjoyed few more than one I recently got from a book review website called Summary Guru , which site carries the headline 'GET INSPIRATION FOR YOUR PAPER WITH AI POWERED BOOK SUMMARIES & ANALYSIS – PLAGIARISM FREE' (Does inspiration need to be plagiarism free? Or just stuff you copy and paste?) To demonstrate the effectiveness of Summary Guru, the release tells us 'Before Watching Netflix's One Day , Know These Five Fascinating Details From The Book' - details produced by Summary Guru. Here they are, with a few of my comments: 1. It's about a single day... across twenty years To be honest, if you don't know this before watching the series, you haven't being paying attention. 2. It deeply explores relationships This is illustrated with 'To quote Emma (the novel’s main female character): “Dexter, I love you so much…and I probably always will. I just don't like you anymore. I'm sorry.”' Yep, deep

Billiard balls and time

I've recently been reading The Blind Spot , which describes how science tends to confuse its idealised and simplified models with reality, and how scientists have traditionally relied too much on reductionism while putting anything that involves human experience into the 'unreliable and subjective' box, even though everything we do in the sciences (as opposed to mathematics) requires the input of human experience. One of the subjects covered at length in the book is time. This is fascinating in the context, because time is the experiential phenomenon that is regarded most differently in physics than it is in reality. Some physicists go as far to say that time doesn't exist at all. Related to this, it is pointed out that many physical processes are reversible in time, where science does not care which way it goes. But in the The Blind Spot the authors emphasise that what we experience is not clock time - the only time that physics regards as real - but duration. Physic

Why is an insect like a leased aircraft?

Lewis Carroll famously came up with the nonsense riddle ‘Why is a raven like a writing desk?’ - which was never intended to have a meaningful answer. But for some reason a piece of science news I read in Physics World inspired the question in the title of this post: why is an insect like a leased aircraft? The leased aircraft in question was one that British Airways borrowed from Aer Lingus. The plane was then repainted in BA colours for the duration. But part of the deal involved repainting the aircraft in the Irish airline’s livery and generally putting it back with the configuration Aer Lingus required before returning it. When the engineers finished, they fixed a little plaque to the instrument panel in the cockpit reading ‘FLY GREEN SIDE UP.’ The science story that made this come to mind was the answer to a long-term puzzle: why do insects seem to be so attracted to lights at night? I had heard the suggestion that they used the Moon to help with navigation - but the study shows t

When is 99% less than 99%?

Asking when 99% is less than 99% sounds like a riddle - but it's not. I recently heard a Sky Mobile radio advert in which they claimed 99% UK coverage. In the 'small print' words at the end, they said this meant they covered 99% of the population. I don't know about you, but unless I'd heard that proviso, I would have assumed that 99% coverage meant you could connect to their service in 99% of UK locations - I expected the figure to be based on area of coverage, rather than population. It might seem like this is splitting hairs, but it really isn't. Let's just imagine an unlikely version of the UK where 99% of the population lived in London (this is, after all, what most advertising people think). Having 99% coverage by Sky's definition would mean that you could only use your mobile phone in 0.65% of the country. The whole point of a mobile is to be able to use in on the move, not just at your home location. Of course, the real UK is not like my imagined