xflower寫到:
請注意前提 (以下略)

mcombbs寫到:
顯然很多人並不了解機率的意思.

想像自己在玩這個遊戲,  玩100次. 換門的人將會贏66次左右, 不換的人只贏33次左右.  這就是2/3跟1/3的差別. 不是說換門就一定會贏, 是說換門贏的機會比較大. 當然如果你一開始就選對門的話就會弄巧成拙, 但問題是你一開始就選對門的機率只有1/3.

不相信的人可以手動或用Excel模擬驗證,  結果一定是換門贏的次數比較多, 不可能是一半一半. 這是個數學題, 正確答案只有一個, 沒有申論的空間.

yiumingl99寫到:
Because of the game rule make it better chance.
Before open any door, you only have 33% to get the gift one.
But after he opened the wrong door, you can change or keep your door, they are both give you 50% to win the gift.

He must open the wrong door later, so acutally this is a 50% chance of game to win.

nelsontata寫到:

I agree this explaination, actually the 1st time selection is just a tricky, because the
host will always open one of the wrong door then to let you select again from 2 doors, so the chance to win this game is 50%.