老师您好，关于上午真题Derivative部分2017年第十题(D)小问，答案中提到information ratio can be false positive when returns are below risk free rate, 但standard deviation不是应该一直都是正数么？(Rp-Rb)的standard deviation可以是负的吗？ 谢谢!

十七题什么意思谢谢

Jensen‘s alpha不是actual portfolio return跟risk-adjusted return之间的差么，那risk-adjusted return要越大的话不应该是alpha越小么

MPS , 等额偿付本金和利息 1.CMOs are created from pools of pass-through securities, 利息和本金有先后顺序 不知我的理解对不？ 2.CMOs are securities issued against pass-through securities for which the cash flow have been reallocated to different tranches.这句话如何理解？谢谢！

视频38：25之后。老师说供大于求是短缺，对吗？

请问答案解析中A is incorrect because the forward price is set in the pricing of the contract such that the starting contract value is zero, unlike contingent claims, under which parties can select any starting value这句话的意思能解释一下吗，什么是starting contract value？以及为何option中参与方能够选择任何starting value

（R14 102） STATUS这块我能不能用BASE法则理解，如图已画？

为啥 deta Y = detay + deta L 代表 sustainable 的 economics growth 啊

我理解contraction risk与市场interest rate有关，为什么有与mortgage rate相关？我理解mortgage rate是mortgageloan的贷款利率，是不变的？

您好！经济百题case 5 第5题的profit问的是以usd为单位，想问如果以sf为单位，profit怎么算？谢谢