选项A“Copula enables the structures of correlation between variables to be calculated separately from their marginal distributions.”说的不是Copula能在两个变量的边际分布中把他们的相关性分离计算出来的意思嘛，说的是在将两个映射后的正态分布整合成Copula时所选用的相关性的计算方式吗？跟您这里回答的算违约概率没关系啊

“Spearman’s rank correlation and Kendall’s τ are ordinal correlation coefficients that should not be used with cardinal financial variables because they underestimate risk by ignoring the impact of outliers.”这个cardinal financial variables是什么意思呢？

老师你好 St−St−1=a 𝜇s − a St−1 Y = α + βX 从St-St-1=aμ-aSt-1推出Y = α + βX，套用到这道题的情景下这里的Y是前后两天的rho之差、这里的X是前一天的rho吗？而β是在为负的情况下（即β=-a）才能表示mean reversion rate吗？

老师，你好，我想问下什么情况下用normal VaR计算Liquidity-adjusted Var,什么时候用lognormal VaR计算，这道题没有表示服从正态分布，为什么会使用Normal VaR?

为什么每次视频解析讲的都比答案解析简单呢…答案解析我都看不懂😓 1.“With duration mapping, a portfolio is replaced by a zero-coupon bond with maturity equal to the duration of the portfolio. The risk of the hypothetical zeros is less than the risk of a coupon bond of comparable maturity.（这前后两句话有关联嘛，前面是说把原债券映射成maturity是久期的零息债，后面拿来跟它比的a coupon bond of comparable maturity是什么？说的不是principal mapping出来的零息债啊。）Therefore, the portfolio VaR using duration mapping is less than the portfolio VaR using principal mapping”然后结尾又得出了duration mapping跟principal mapping的对比结论😓 2.“According to the definition and the question specification of buckets, both VaRs should be the same.Option D is incorrect because of the same reason for the correctness of Option A.”这句话啥意思看不懂……

The diversified VaR is lower due to two factors. First, risk measures are not perfectly linear with maturity.求解释…

老师你好 这道题D选项有个疑问，如果它指的是用delta-normal或gamma法算债券的VaR，那不是假设利率为正态分布求出利率的VaR再代入公式直接求债券VaR的吗，那用到的是利率的mean和sigma而不是这个债券组合的mean和sigma诶。

这道题可以用z=x-pT/sqr(p(1-p)*T的公式来计算吗？

C选项什么是downstream impact？

A是什么意思，当市场环境改变时，单一业务条线怎样导致了RAF的变化？