﻿ #14 Statistics & Context :The Irrational World Blog by Stew Green
#14 Statistics & Context
The Irrational World Blog 2011

 BBC Radio 4 : More or Less prog : Double Yolk Example Original Article on BBC website - They got a box of normal eggs and wow the first 4 they broke were all double yolkers - Wow what's the odds of that ? - Well since they say 1 in 1000 eggs are double-yolkers then surely the odds are 1000x1000x1000x1000 (That's where he should have stopped ..WHY ?) -then he said well actually in younger flocks the odds are 1 in 100 so it's 100x100x100x100 - then they opened the 5th " it's a double" ..and then the 6th " it's a double" - I'd like to say I worked out straight away, but I didn't. I have learnt this ability to when something strange happens to just suspend belief not rush to a conclusion. So when I watch the conjurer Derren Brown I don't really try to work it all out, I just accept it. Many hours later I often suddenly realise "ah that's how he probably did it that's a ridiculously simple trick". If the trick is similar to another previous one I can sometimes see it straight away. - In the egg case I just let it pass ..What I did realise was that it's a case of “too incredible to be true” ..so there's something going on and then 30 minutes later I got a tweet david Spiegelhalter rather unsportingly pointed he'd debunked this already.. The article didn't give the answer straight, but pointed that it wasn't straight line thinking ..and then a Google found a comment mentioning that since there double yolk packing lines and suggested they'd run out of special boxes and so used a normal box. - STOP.. rewind ..of course the problem is assumptions and jumping to conclusions. Yes in the whole of egg totality double-yolkers are 1 in 1000, in 1 in 100 in farms with only young hens, but it's wrong to assume that this box came from there. Context is everything you can't just assume it was a random distribution. - In the context of it being a double yolk packing line the odds aren't 1 in 1000 they are 1 in 1, so of course the 4th and then 5th eggs were double yolks. - Lesson : don't take things at face value and beware extrapolating hypothetical to real life : “Too incredible to be true” .. means the context is not what it first seems .. in a mathematical context they have assumed a random sample but they were wrong to cos clearly in a double yolker packing line the chance is not random (BTW I guess that day, they had a certain number of orders for double yolkers and when that was fulfilled the remaining eggs were just boxed as large to fulfill the orders for large) Micro Lives and Micromorts - good but technically written Micro Lives and Micromorts BBC News totally misreport "Three-fold variation in bowel cancer" & fail to understand even when it's explained to them - "Staggeringly statistical cluelessness from BBC News Editor" He Wrote - Explanation Basically said cos numbers in one are is 3 times another, there must be something wrong with the care, but when you check the group size they are so small that the variations fall well within the random pattern. , BMJ Explanation - "I love BBC Science, but BBC news doesn't half fuck up on it's science" Better Stats in future ? - We need a stats police - stats for PR rules - bads stats in establishment are usually exposed by BBCr4 More or Less but now ex presenter Andrew Dilnot is to Chair the UK Statistics Authority
 Update - They are still sticking to their line that the context is a young underdeveloped flock - Tim contradicted himself when he said "doubles are premium so they are unlikely to put them to put them in normal boxes" previously he said "well they don't scan every egg" .. I expect they do with a light scanner on the packing line - MoL explanation is possible, but Spiegelhalter's explanation that they came from a double yolk packing line is much more likely if your 1 in 1000 or 1 in 100 is true - If 5 out of 6 then MoL explanation is 100%, 6 out of 6 then both MoL & Spiegelhalter's explanation fit, but surely Spiegelhalter's explanation is much more likely to occur. - actually Daily Mail Article has many intelligent comments. Here's the best "Egg producers check eggs with bright light to spot the double yolks as they are worth more and they are put to one side. If at the end of the day they have too many the put them with the normal ones. And as for the odds that have been quoted here it would mean every person in the world would have to buy over 150'000'000 boxes of eggs for one person to get all double yolks. All this proves is you can't trust a statistician." - paul, Melton U.K., 04/2/2010 06:43 - click show all comments to see all 80 - last-word.com/ also tackled it 2008-08-20 18:01:00 - Also last year the Independent - Explanation 2. The young underdeveloped flock context is possible ..especially if the 1 in1000 is actually more like 1 in 50 normally and 80 in 100 in young farms - If a flock lays 1000 eggs and 200 are DY then during packing most boxes would have no DY, some mixed, and very few all DY ..maybe 130, 37, 3 - If 1000 eggs reach the DY packing line and they need 600DY then the first 100 boxes are all DY and the next 70 DY in normal boxes since there are not dozens of people with 4DY, 5DY to every 6DY I'd go with Spiegelhalter's - You might argue that the number of DY possible flocks feeding normal packing lines is much bigger than number of specialist DY lines, but even if it was 20 to 1 there's still be more 6DY normal boxes coming off DY only packing lines - Explanation 3. It's also possible "her friend" just replaced all the eggs with those from a double yolker box ‎Eggs whites are NOT a magic treatment for burns - I got a chain letter from India yesterday "Egg whites . . . Who Knew? " 30s of Googling shows 2 articles saying IT'S BUNK - urbanlegends.about.com - snopes.com - another thing is that in India where the chain letter came from salmonella is quite common in eggs - The NHS has a great comprehensive guide then click on the TREATMENT , and COMPLICATIONS tabs - A summary - Remove any clothing or jewellery near the burnt area of skin, but do not attempt to remove anything that is stuck to the burnt skin because this could cause more damage. - The main thing is for burns hold under cold tap for minutes, no ice. - For serious burns gets to treatment ASAP - The main thing is to KEEP INFECTION OUT, as ever don't use creams, ointments antiseptics etc . as these can harbour bugs, rather cover the wound with clingfilm or a clean plastic bag - HEALING : Superficial burns protected as above will heal naturally. When it's safe to put something on, aloe vera may work .. but whenever you put anything on a wound you have to be careful of infections. - There is a treatment with honey e.g. flood the area of the wound and wrap in clingfilm. The NHS don't use this as though it's traditionally effective & risk of infection is much lower than other substances it's unproven scientifically and there maybe be issues e.g. danger of allergy to pollen and some bacteria spores can be found in honey. The " Cochrane review" recently published in UK newspapers concluded "There is insufficient evidence to determine the effect of honey compared with other treatments for burns or in other acute or chronic wound types. Honey may improve healing times in mild to moderate superficial and partial thickness burns compared with some conventional dressings."
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