### Bayes' Theorem—the maths tool we probably use every day, but what is it?

Will he or won’t he hit the bullseye? Using Bayes’ Theorem, your prediction will be based on how the current match is going – and how he’s played in the past. Credit: Flickr/Marjan Lazarevski, CC BY-ND Our world view and resultant actions are often driven by a simple theorem, devised in secret more than 150…