Spurious formulae - from the perfect joke to the perfect penalty kick - are used by PR firms to get their clients' products mentioned in the media.
Is it just a bit of harmless fun? Or pernicious maths vandalism?
Science journalist Simon Singh debates the question with Len Fisher, who pioneered the tactic with his formula for the best way to dunk a biscuit.
Calculating copyright infringement
The Black Eyed Peas song Boom Boom Pow is currently a popular download on The Pirate Bay
Government advisers say seven million people in the UK are engaged in downloading files illegally over the Internet.
The number was quoted in research commissioned by the Strategic Advisory Board for Intellectual Property Policy.
But in fact the figure actually comes from earlier private research commissioned by a music industry lobby group that was never published.
Oliver Hawkins investigates a widely-reported statistic.
State of the statistical nation
Jil Matheson is the new National Statistician - can she keep Britain's numbers in order?
The new National Statistician starts work this week.
Jil Matheson replaces Dame Karen Dunnell as the person responsible for keeping the nation's numbers accurate, independent and accessible.
She joins Tim Harford to discuss some of the challenges she faces in the role, including the 2011 census.
The great loyalty debate
Should Tim stop referring to listeners as "loyal"? We asked for your opinions and the results are in.
(Although the sample is not random, the sample size is tiny, the respondents are self-selected and the polling method is highly questionable.)
Why does England lose?
Would it have made Gazza feel better if he'd known statistics were to blame?
And why does Manchester United win?
How much does the manager matter, and how much is down to cold hard cash?
Economist Stefan Szymanski brings statistics to bear on these and other questions to explore what really accounts for the success and failure of football teams.
An offer you can't refuse
One of our colleagues spotted this apparently tempting offer in Japan.
If you have your own examples of innumerate adverts and signage, we would love to see them. Our email address is: firstname.lastname@example.org
I remember being told in class one day a thing that has stuck in my mind ever since. When mention was made of statistics the instructor told us to: " ...always remember, STATISTICS are like bikinis : what they reveal is interesting, but what they hide is vital !!" I have never forgotten that description, and whenever I hear statistics being pumped out by whatever organisation I always feel they are hiding something vital. Graham Laughton
Until I recently read about this, I didn't realise this kind of stuff was commissioned so I always wondered why on earth universities would waste their time on stuff like this at the same time as moaning about funding. For anyone who doesn't know about this, they will likely be thinking universities are wasting funding calculating things like the best shopping day before Christmas. Not great PR for the scientific community really. Joanne Duff
This is blurb spotted on the back of a Clarks guide to children's foot health and the importance of poorly fitted shoes. It says: "Did you know? Every time your child takes a step their heel strikes the floor with force equivalent to twice their body weight. So, during the course of a day, an average child's feet will carry the equivalent weight of just over 2 blue whales." Does this count as junk maths? Rob Abbott
In your feature on "Calculating copyright infringement" you missed the assumption that everybody who uses file sharing software is *illegally* sharing files. That is not the case -- such file sharing software is commonly used for entirely legal purposes (for example, the official distribution for Sun Microsystems' popular OpenOffice.org software depends on such file sharing software). Again, this leads to an overestimate of the number of people illegally downloading files. Tim Rowe
If the question posed was whether the respondent had used file sharing software, the results would not have estimated the level of illegal downloading. P2P networks are not illegal in themselves and those using them for nefarious purposes are only a subset of all users. Even the BBC used to use 'file sharing software' (Kontiki) in the iPlayer. Charles Quekett
Regarding your item on copyright infringement, it seems to me that there is something invalid about the basic assumption that each of these people should be afforded equal weight in the derivation of the figures. Surely the person who downloads the odd song or film is statistically insignificant in comparison to the smaller number of serious, professional pirates who are downloading files in their thousands? It might also be of some relevance whether files are downloaded solely for personal use (= inevitably self-limiting), or are intended for wider distribution for profit. One way or the other, to quote a statistical figure based solely on a head count of ownership of software capable of downloading would seem to be both misleading and meaningless.Dr David Gasking
Your feature today on energy-saving light bulbs was interesting, but the question is whether I would save more energy by throwing out my incandescent bulbs and replacing them with energy-saving bulbs before the end of their life?Jon Mack
I've used energy saving light bulbs for 20 years. Whilst the price per bulb has come down over that time, bulbs I've bought recently seem to fail much sooner - nothing like the stated average life. This means I have to take the bulbs to a particular recycling site due to their composition. Has anyone tested whether the average life claim is still true?Peter Templeton
I have a 7 watt bulb in my house that I bought when my first grandchild was a baby so that I could leave the landing light on all night for him without sending my electricity bill through the roof! It is still working and is switched on at least once every day and often gets left on all night.
I think these bulbs are marvellous and have them all over the house now. Shirley Williams
You said that a CFL light bulb had 16 times the life of an incandescent one, but no mention was given of where this statistical figure had come from. Last year I purchased seven CFL bulbs and three of them have already had to be replaced - on the other hand I have one 40 watt incandescent bulb that is nearly fifty years old.
The extra energy of incandescent bulbs in domestic rooms is not lost as it helps to heat up the room quite efficiently, keeping any heating thermostat off for longer and hence reducing heating energy in compensation.Anthony Harrison
Why is it that statisticians refer to numbers such as national debt figures as xxx number of pounds per each person. I don't have any debt and I cannot believe I am the only person in the country with no debt. Lyndon Antle
I listened to your recent interview with Jill Matheson, the incoming chief of the ONS. I thought you asked some important questions about the credibility of the ONS, but felt that she seemed to be in a state of denial. I would say she has some work to do to re-establish the ONS as a credible source for national statistics but seems to be oblivious of the challenges she faces.
As a member of the public I have tried to make use of the ONS website to verify claims made by politicians and I came away disappointed. Not only are all the published statistics highly aggregated but they are not readily available in machine-readable formats. I found it very hard to even validate the data that was being presented and was not very happy about the way it was classified. GDP statistics are not broken down by industry for example, but in a wholly useless way by function (agriculture, business services, mining etc.)
But what is really missing is any way of validating the statistics in the first place. What Ms Matheson must realise is that the days when we could take government departments at their word are long gone, and some way of comparing data for internal consistency and correctness is essential. This has absolutely nothing to do with anything that might be called the British 'character'. It is a basic principle of the scientific method. Christopher Tipper
The analysis of football "statistics" appears to me to be flawed as football is partly skill and partly chance. Think of the team that does not win but hits the goal-posts several times. The analysis quoted on the programme did not appear to take into account the element of "luck" that there is in football. Arthur Boon
I was astonished to hear the item about the England football team's qualifying records. The contributor stated that the record of the team that qualified for the 1990 World Cup was "exactly the same" as that which failed to qualify for the 2008 European Championships. This is blatantly untrue!
The 1990 team had a record of 3 wins, 3 draws and no defeats. As you only got two points for a win back then, that gave them 9 points in total out of a possible 12 - a percentage of 75%.
The 2008 team had a record of 7 wins, 2 draws and 3 defeats. Using two points for a win this would have given them 16 points out of a possible 24 - a percentage of 66.67% and clearly inferior.
If you use the three points for a win system that was utilised for the 2008 qualifiers, the percentages are closer : 66.67% for the 1990 team and 63.89% for the 2008 team.
Whichever method you use, the 1990 team has the better record. Matthew Hill
I have a photo of an in-store sign at Lidl, offering low energy lightbulbs.
"1 pack 49p" (Pack meaning 1 bulb) and next to that "5 for 40p - you save £2.05"
Surely it means 40p EACH if 5 are bought: saving 45p?
No; it really was 1 bulb for 49p or 5 bulbs for a total of 40p! Andrew Currie
I went shopping in Asda on Saturday and at the check out I noticed that they charged me £1.25 for a bottle of chilli sauce and yet I was sure that there was a label on the shelf stating it was a £1. I went back to the shelf to check and noticed it said 2 bottles for £1- one bottle for £1.25. I went to Customer service with another bottle and received my 25p refund!Sheila Treacy
BBC Radio 4's More or Less is broadcast on Friday, 4 September at 1330 BST and repeated on Sunday, 6 September at 2000 BST.
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