NO.PZ2022122601000044
问题如下：
O'Reilly responds: Another bias results from the use of appraisal data in the absence of market transaction data. Appraisal values tend to be less volatile than market determined values for identical assets. The result is that calculated correlations with other assets tend to be biased upward in absolute value compared with the true correlations, and the true variance of the asset is biased downward.
With respect to his explanation of appraisal data bias, O'Reilly most likely is:
选项：
A.incorrect, because the true variance of the asset is biased upward. B.incorrect, because calculated correlations with other assets tend to be biased downward in absolute value C.correct
解释：
Correct Answer: B
O'Reilly's explanation of appraisal data bias is incorrect because calculated correlations with other assets tend to be smaller in absolute value compared with the true correlations. O'Reilly is correct in that appraisal values tend to be less volatile than market-determined values for identical assets, and the true variance (and standard deviation) of the asset is biased downward.
中文解析：
O'Reilly对评估数据偏差的解释是不正确的，因为与其他资产的计算相关性在绝对值上往往小于真实相关性。O'Reilly是正确的，因为对于相同的资产，评估值往往比市场决定的价值波动更小，而且资产的真实方差(和标准差)是向下倾斜的。
- tends to be biased upward, 是翻译为高估了嘛
- 答案中的最后一句，真实的方差是向下倾斜的，怎么理解？
