问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
第二个是对的吧，既然是STRESS PERIOD，那相关性肯定是上升的呀，怎么会不知道UPWARD 还是DOWNWARD呢
KellyBai · 2019年04月14日
老师多问一句，经济情况好的时候，correlation volatility 高是什么道理呢？
-- performance 要么就都相关，要么就都不相关？
太绕
orange品职答疑助手 · 2019年04月14日
同学你好，根据这里的表格，correlation volatility 最高是在经济处于正常的时期。当经济好、处于扩张时期时，相关性的波动率是最低的呀= =
KellyBai · 2019年04月15日
经济“正常”的时候，correlation volatility 高是什么道理呢？
orange品职答疑助手 · 2019年04月15日
我觉得可以这样理解：因为经济是处于normal状态的，它可能变好也可能变得更差，所以相应地相关性往高了变或者往低了变的可能性都不小，所以在样本期1972-2012年内，反倒是经济处于normal时correlation的波动性 更大些
NO.PZ2016070202000015 问题如下 Bren Williams is a risk analyst who wants to mol the pennbetween asset returns using copulanmust convinher manager ththis is the best approach. Whiof the following statements are correct?I. The pennbetween the return stributions of portfolio assets is criticfor risk measurement.II. Correlation estimates often appestable in perio of low market volatility anthen become volatile in stressemarket contions. Risk measures calculateusing correlations estimateover long horizons will therefore unrestimate risk in stresseperio.III. Pearson correlation (ρ) is a linemeasure of pennbetween the return of two assets equto the ratio of the covarianof the asset returns to the proof their volatilities.IV. Using copulas, one cconstrujoint return stribution functions from marginstribution functions in a wthallows for more genertypes of pennstructure of the asset returns. A.I, II, anIII B.II anIV C.I, II, III, anIV I, III, anIV is correct. The pennis critical, so statement I. is correct. The usuPearson correlation is a linemeasure of pennce, so statement III. is correct. Statement IV. is also correct. For statement II., correlations inechange over stresseperio, but it is not clewhether this biases long-term correlations upwaror wnwar Also, the effeon the portfolio risk pen on the positioning. Hence, there is not enough information to support statement II. 老师解析不是说A对的吗？那应该四个表述都对啊
NO.PZ2016070202000015问题如下 Bren Williams is a risk analyst who wants to mol the pennbetween asset returns using copulanmust convinher manager ththis is the best approach. Whiof the following statements are correct?I. The pennbetween the return stributions of portfolio assets is criticfor risk measurement.II. Correlation estimates often appestable in perio of low market volatility anthen become volatile in stressemarket contions. Risk measures calculateusing correlations estimateover long horizons will therefore unrestimate risk in stresseperio.III. Pearson correlation (ρ) is a linemeasure of pennbetween the return of two assets equto the ratio of the covarianof the asset returns to the proof their volatilities.IV. Using copulas, one cconstrujoint return stribution functions from marginstribution functions in a wthallows for more genertypes of pennstructure of the asset returns.A.I, II, anIIIB.II anIVC.I, II, III, anIVI, III, anIVis correct. The pennis critical, so statement I. is correct. The usuPearson correlation is a linemeasure of pennce, so statement III. is correct. Statement IV. is also correct. For statement II., correlations inechange over stresseperio, but it is not clewhether this biases long-term correlations upwaror wnwar Also, the effeon the portfolio risk pen on the positioning. Hence, there is not enough information to support statement II.老师，allows for more genertypes of pennstructure of the asset returns，是什么意思，是指原来累积概率分布G直接的相关性结构么？还是指转换为标准正态分布函数后的相关性结构？
NO.PZ2016070202000015问题如下Bren Williams is a risk analyst who wants to mol the pennbetween asset returns using copulanmust convinher manager ththis is the best approach. Whiof the following statements are correct?I. The pennbetween the return stributions of portfolio assets is criticfor risk measurement.II. Correlation estimates often appestable in perio of low market volatility anthen become volatile in stressemarket contions. Risk measures calculateusing correlations estimateover long horizons will therefore unrestimate risk in stresseperio.III. Pearson correlation (ρ) is a linemeasure of pennbetween the return of two assets equto the ratio of the covarianof the asset returns to the proof their volatilities.IV. Using copulas, one cconstrujoint return stribution functions from marginstribution functions in a wthallows for more genertypes of pennstructure of the asset returns.A.I, II, anIIIB.II anIVC.I, II, III, anIVI, III, anIVis correct. The pennis critical, so statement I. is correct. The usuPearson correlation is a linemeasure of pennce, so statement III. is correct. Statement IV. is also correct. For statement II., correlations inechange over stresseperio, but it is not clewhether this biases long-term correlations upwaror wnwar Also, the effeon the portfolio risk pen on the positioning. Hence, there is not enough information to support statement II.请问ii为什么不对。。。
NO.PZ2016070202000015 请问 Pearson correlation (ρ) is a linemeasure of pennbetween the return of two assets equto the ratio of the covarianof the asset returns to the proof their volatilities. 这个ratio of covarianto volatility 的结果不是β吗？
NO.PZ2016070202000015 以下个人理解，老师看看是否对 1.正常时期波动小，压力时候波动大，但是波动大可能导致ρ往下走得多，也可能导致ρ往上走得多。 2.正常时期ρ小，压力时期ρ大，这个只是大部分情况来说是这样，特殊情况有可能压力时期ρ减小？ 3.考虑ρ变大或者变小，还要考虑头寸的问题，例如全部投了equity，那么ρ变大反而是好的，风险会更小？ 所以综上所述，statement II就是错的，对吗？
它前半句也有问题，become volatile in stressed market conditions不一定，correlation volatility最高的是经济正常时期。