Watched a movie called 21 last night. Kevin Spacey plays a lecturer that teaches his clever students to beat casino's at blackjack. In the movie he poses a question to his students that I didn't understand.
A quizmaster offers you the chance to select any of the 3 doors. Behind 2 of the doors are goats and behind the remaining door is a car. You select the door behind which you believe is the car. The quizmaster then opens one of the other doors and reveals a goat. To my mind this leaves you with a 50/50 shot at winning the car or so I thought. The quizmaster then offers you the opportunity to change your original selection prior to him opening the next door. The movie argues that statistically you should change your selection to give you a better shot at winning the car. That bit I don't get.
Can someone explain the reasoning or is the movie just kidding?
A quizmaster offers you the chance to select any of the 3 doors. Behind 2 of the doors are goats and behind the remaining door is a car. You select the door behind which you believe is the car. The quizmaster then opens one of the other doors and reveals a goat. To my mind this leaves you with a 50/50 shot at winning the car or so I thought. The quizmaster then offers you the opportunity to change your original selection prior to him opening the next door. The movie argues that statistically you should change your selection to give you a better shot at winning the car. That bit I don't get.
Can someone explain the reasoning or is the movie just kidding?
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