Sortino ratio calculation: MAR is pre-setted, not the kind of mean of sampl, MAR WILL NOT alter the degree of freedom, why the denominator has the way to get the deviation as the samplling deviation computation? The function should be wrong, IF no return is below the MAR, whta is meaning of the function? sum o to o, makes no sense to the function. so, T sould be sums from 1, not zero, to a certain count. thanks!

Sortino ratio calculation: MAR is pre-setted, not the kind of mean of sampl, MAR WILL NOT alter the degree of freedom, why the denominator has the way to get the deviation as the samplling deviation computation?

请问为什么floater的duration是0？

老师，为什么这里面的r=0.1，不是0.2。就是这句话不是说6个月远期收益为2%吗？而且不是应该是0.039-q吗？收益不是0.2吗？不是相当于q=0.2吗？为什么是r？希望老师能讲一下这个题，谢谢了。

为什么分母的指数是0.25*2？不是90/360吗

A bank has sold USD 300000 of call option on 100000 equities，使用equity对冲期权，0.5是期权的delta，为什么不是用0.5*300000（期权的价值）呢？

期权中，long方的风险为什么通常来说比short方要大？

不是应该从左往右数吗，-1.87%是第四个呀？

那如果是负相关是不是小于EL？

1. 6%不是半年期利率吗，为什么付款日收到的钱是30000不是60000？