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- [讲解员] 从因到果之路[br]黑暗又凶险

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但我们拥有[br]计量经济学的强大武器

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请看，这就是威力最强的[br]随机分配之剑

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它直逼因果问题的核心

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我们先来看看我们手中[br]最强大也最昂贵的武器 --

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随机试验

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- [学生] 太棒了

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- 每种计量方法的使命[br]都始于因果问题

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清晰的问题[br]才能带来清晰的答案

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而随机试验能够提供[br]最清晰的答案

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我们来看看[br]随机试验是如何

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对因果问题给出[br]格外有说服力的答案的

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- [Josh] 正如一把精心打磨的宝剑

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随机试验直指因果问题的核心

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它能用来创造[br]深具说服力的同类比较

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但就像其他精心制造的武器一样

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随机试验十分昂贵[br]运用起来耗时也很久

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- 随机试验起源于医学研究

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当时被称为随机

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