Back in the 1970s, the popular television game show “Let’s Make a Deal,” hosted by Monty Hall, became the unexpected face of a classic probability problem — now often called the Monty Hall problem.
In the most celebrated version of the show, contestants were given a choice of three doors. Behind one door was a fancy sports car. Behind each of the other two doors was something not as grand: a goat. Once a contestant made their choice, Hall would open one of the unchosen doors that he knew would reveal a goat. That left two doors still unopened, one with a goat and one with a car. Then came the ultimate question. “Do you still want what’s behind door number one? Or would you like to switch to the other unopened door?”