My cousin posted an article about Marilyn vos Savant on Facebook. Twenty-five years ago, she "solved" the Monty Hall Problem, and ten thousand people wrote in to tell her that she was wrong. It was simply that, if presented with three doors, told that two doors each have a goat, but the third has a car, and told to choose one, what is the chance of correctly choosing the door hiding the car if you change your mind after shown the third door?
The writer said that you would think that you have a fifty-fifty chance regardless, but vos Savant argued that it would be two-thirds.
Many paragraphs later, I understood that, if shown the car, your chances of choosing the car increase to 100% if you chose another door, but change your mind--presumably to the open one showing the car. If you do not choose the car after seeing it, there is a 100% chance that you are an idiot.
Seriously, I do not use that term lightly. There is only one car, you are shown the car, so why would you say "No thanks, the one and only car is behind another door?"
So, you are correct in thinking that you have a 50-50 chance whether you change your mind or not, assuming that the third door does not have the car.
http://priceonomics.com/the-time-eve...ign=pockethits