Most people are already on board with the idea of a “bet worth taking,” in at least some contexts. To give a simple example, suppose someone offered you a bet in which you roll a normal six-sided die. If it lands on a six, you win $200; if not, you lose $10. Should you take it? Almost certainly. This is a good bet for you—and you can see exactly how good it is by calculating its expected value. That’s the average amount a bet pays out each time, if you were to take it an infinite number of times.
