The Monty Hall Problem

“Are you SURE you don't want to switch your answer?”

Math/Logic problems are often the subject of debate, but this is perhaps the granddaddy of them all. It's called “The Monty Hall Problem” named after the host of the popular game show “Let's Make a Deal!” It became subject of a national uproar when it appeared in an “Ask Marilyn” column in Parade magazine in 1990. The “problem” is this: you are on a game show with 3 doors, one of which has a car on the other side, the others have a goat. You choose Door #1. Before showing you what you've won, Monty shows you what's behind one of the other doors – a goat – and asks you if you would still like what's behind Door #1. The question is, is it to your advantage to switch your choice? Marilyn said statistically it is (2/3 chance vs. 1/3) but the public refused to believe her. 10,000 readers chimed in and most were against her, including several PhDs. Eventually, many people “switched” their answer and sided with her, but not without continuous debate. In 2009, a 208-page book on the Monty Hall Problem was published by Oxford University Press.