来自《耶鲁大学开放课程：金融理论 第9集 第9集》

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  that in some years, it's got a lot more money.
  比如有时赚的很多
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  So if those were the years that lost money,
  有时又赔的很多
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  and the years when it hardly had any money were the years it
  有时快要破产有时又大赚特赚
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  made money, just taking the average,
  你做的仅仅是取平均数
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  the multiplicative average, the geometric average of all
  取所有年份投资回报率的
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  those yearly rates of returns, would give a misleading figure.
  几何平均 而几何平均会有偏差
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  Well, the yield also gives a somewhat misleading figure,
  收益率方面也存在些偏差
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  and I don't want to spend too much time on why it might be
  我并不想太多解释为什么有偏差
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  misleading, but I'll give you just an
  但我会给你举一个
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  example.
  例子
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  Suppose that the cash flows happen to be 1,
  假设现金流为1
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  -4, and 3.
  -4 以及3