来自《耶鲁大学开放课程：金融市场 第6集 第6集》

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  Sometimes it's hard to tell.
  有时候这很难区分
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  I thought--can you tell the difference
  你们能够区分出
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  between a random walk and an AR-1?
  随机漫步模型和一阶自回归模型吗
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  It seems to be coming back faster,
  后者看起来回归得更快
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  so that looks different.
  所以有些不同
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  Well, with ρ = .95 I guess it does look noticeably different
  当ρ=0.95时 区别还是比较明显的
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  because it's coming back pretty fast.
  因为它回归地相当快
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  I have 130 years of observations
  我有130年的观测值
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  and it's coming back 5% of the way every year,
  它每年都回归5%
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  so in five years it's 25% of the way back.
  所以5年它就回归25%
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  I've got the cord too tight
  我假设约束很紧
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  so it's not fooling you, right?
  所以结果相对接近事实 是不是