Mathematician's forecasting equation could help stocking-wearers out of seasonal tight spot

A statistician – and former 'Robin Hood' – has developed a mathematical formula to help people decide what type of tights to wear depending on the weather.

Dr Hind was asked to come up with the formula by BBC Radio Nottingham
I refined it to include wind speed so that on blustery days the equation predicts thicker tights.

Dr James Hind, Nottingham Trent University

A statistician – and former 'Robin Hood' – has developed a mathematical formula to help people decide what type of tights to wear depending on the weather.

Dr James Hind, a Lecturer in Statistics at Nottingham Trent University, developed the formula to advise on what level thickness – or denier – to wear when faced with varying temperatures and wind speeds. The equation can also determine footless tights for warmer days, or – on particularly chilly days – will recommend leggings.

Dr Hind was asked to come up with the fun 'tights forecasting equation' by local radio station BBC Radio Nottingham. The station came up with the idea of a stocking forecast to help their listeners with the morning denier dilemma – which tights to wear today?

BBC Radio Nottingham now plan to refer to the formula over the next few weeks to provide a daily stocking forecast during the breakfast show weather.

The formula works by typing in the two variables – temperature and wind speed – for any given day. It is designed using the 'sigmoid curve' to create a scale which can calculate the denier of fibre required. The curve allows for very little change at the extremes – very hot or very cold – but lots of change in the middle temperature ranges, where a solution is not as clear cut.

As well as being a mathematician, Dr Hind used to play Robin Hood at former Nottingham tourist attraction The Tales of Robin Hood, so is no stranger to the trials and tribulations of wearing tights.

Dr Hind, who is based in the University's School of Science and Technology, said: "The equation started out as a few observations. When I plotted the points I could see I needed a sigmoid function – so called because of its 'S' shape – and soon realised that it needed the maths constants e and pi to work properly.

"In maths we sometimes use the sigmoid function to help split binary outcomes, for instance hot and cold, tights or no tights, into a range of values. This let me assign different denier strengths to different temperatures. No matter how cold or warm it gets, the equation will work fine. I refined it to include wind speed so that on blustery days the equation predicts thicker tights.

"I weighted the equation to use 110 denier as the thickest possible tights - this was always good enough to keep my legs warm back when I played Robin Hood."

Sophie Shardlow, BBC Radio Nottingham Editor, said: "The stocking forecast has certainly got legs, being picked up by lots of media outlets! I'm delighted our fun idea of using maths to help women decide what to wear each morning has proved so popular."

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Mathematician's forecasting equation could help stocking-wearers out of seasonal tight spot

Published on 10 September 2015
• Category: Press office; Research; School of Science and Technology

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