在Black Model里，underlying如果像股指期货这种，会有连续股利，这时的d1（如图）是否在分子上还需减掉连续股利×T这部分

在BSM计算期权时，如果题目给的是r=5%，需要把它算成一个连续复利率，还是直接把它看成就是个连续复利率

为什么说MP=AP时，AP最大？过程如何推导？

NPV不是一定得是正的才具备投资价值吗？

为什么卖价大于买价才能获利啊。卖价是五块，买价只肯出四块，不是买不进来吗？

老师，请问Fixed charge coverage中的 分子的lease payment是作为lessee的OL还是lessor的OL，那分母的lease payment是作为essee的OL还是lessor的OL？麻烦老师解读一下。谢谢

A mutual fund manager wants to create a fund based on a high-grade corporate bond index. She first distinguishes between utility bonds and industrial bonds; she then, for each segment, defines maturity intervals of less than 5 years, 5 to 10 years, and greater than 10 years. For each segment and maturity level, she classifies the bonds as callable or noncallable. She then randomly selects bonds from each of the subpopulations she has created. For the manager’s sample, which of the following best describes the sampling approach? A Stratified random. B Simple random. C Systematic. 上一题  正确答案A 您的答案B 本题平均正确率：92% Sampling, time-series and cross-sectional data难度：一般 推荐：      答案解析 In stratified random sampling, one divides the population into subpopulations and randomly samples from within the subpopulations. 请问： 1.分层是一定要求每组中有固定比例吗？ 2.系统抽样是每组中第Kth个的那种吗？

kinked model中MR为什么会有缺口？

请老师看下，int rate option里 d1是否是我写的这个式子

老师，Cost Approach 默认是Net 还是 Gross lease呢？我不懂为什么天花板的问题要减去5万？我觉得老房子天花板更高所以材料费应该更高呀，难道不是应该比新房子更贵5万嘛？