An apple-a-day will actually keep the doctors away, according to a study in the Christmas edition of the British Medical Journal. It generated headlines around the world. But were the media right to take the story so seriously? Tim interviews one of the study’s authors and critic Paul Marantz. And, mathemagical mind-reading: Jolyon Jenkins reveals the maths behind a classic long-distance mind-reading card trick. Presenter: Tim Harford. Producer: Ruth Alexander. This programme was first broadcast on the BBC World Service.