Or, in this case, the non-luck of the draw. Ben Goldacre, over at Bad Science, draws our attention to the case of Lucia de Berk.
The Luck of the Draw
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One response to “The Luck of the Draw”
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Probability is a tricky subject, as I recall from my university days. For example I was able to baffle a group of educated oil industry types the other day when at a workshop. There were around 30 people, and I bet them that it was almost certain that two of them would share the same birthday. There was general disblelief at this, people thinkng that you would need many more people (at least 365/2 people) than this for it to be likely that two people in the group shared a birthday, yet in fact two people quickly identified themselves as having the same birthday, and I was not lucky. This is a well known probability theory issue called the "birthday problem". In fact it needs just 23 people in a group for it to be more likely than not that two people will share a birthday. There are many such things in probability that are not obvious to most people.
While such things may be counter-intuitive, it is sad in the court case that the defence team did not just call up a universoty maths department to check the prosecution’s figres.
Geoff Coupe's Blog 
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