But everyone who guessed in this way went low, rather than high. It suggests that there is some form of systemic bias in play. - David Franklin

With these issues in mind, Dan has a unique way of tying exams into the learning process. After attending a workshop run by the Nobel Prize winner Carl Wieman, he was converted to the idea of two-stage exams. The first stage of the exam is the same as any other. The second stage brings the students together in groups of four, and gives them all a subset of the questions they just answered in the first stage. The students are encouraged to discuss their answers in their groups, and they all submit a second version. Groups who manage to improve upon the students’ individual scores get a small boost in the final outcome.

What is the probability that at least two people in a group of 20 people will have the same birthday?

Einstein is supposed to have remarked that “education is what remains when one has forgotten everything they learned at school”.