DiscoverTaking Maths Further PodcastEpisode 1: Crime Scene Investigation, forensic science and Bayes' theorem
Episode 1: Crime Scene Investigation, forensic science and Bayes' theorem

Episode 1: Crime Scene Investigation, forensic science and Bayes' theorem

Update: 2014-06-24
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Description

This week the topic was Bayesian statistics. We interviewed Emma Rixon from Nottingham Trent University about her work as a crime scene investigator and how forensic science uses Bayesian probabilities.




Bayesian probability:




Puzzle:
I have a bag containing 47 black marble and 53 white marbles. I draw out two marbles. What’s the probability that the second marble I draw out is white, given that the first marble I draw is black?



Solution



The bag contains 47 black marbles and 53 white marbles. This means the probability
of drawing a black marble first time is 47/100, but then having done so there are 46
black marbles and 53 white marbles. The probability of drawing a white marble the
second time is then 53/99, instead of 53/100, which would be the probability of
drawing a white marble the first time.

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Episode 1: Crime Scene Investigation, forensic science and Bayes' theorem

Episode 1: Crime Scene Investigation, forensic science and Bayes' theorem

Peter Rowlett and Katie Steckles