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
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