survivorship bias & backfill bias感觉都是把表现好的基金放入portfolio 从而使return被高估， 如果区别它们？是否backfill bias 只是因为加入了好的基金，使得整体portfolio的历史表现被高估呢？

老师，9题麻烦您举例说明一下谢谢

疑问

为什么average age=accumulated depreciation/depreciation expense?

想请问下图片这道题目解题过程中最后一步100*（1+6%/2）89/180的89/180次方如何用计算器按出来啊，现在也是通过9上方的yx键吗 但是我加了括号还是按不出来 麻烦把具体按计算器的步骤告诉我一下 谢谢！考试中这种有分数次方的题会经常出现吗

你好，本题是金程题库里，但是这个答案解题好像不是说这一题，请确认，

原版书课后第18题： Pierre-Louis Robert just purchased a call option on shares of the Michelin Group. A few days ago he wrote a put option on Michelin shares. The call and put options have the same exercise price, expiration date, and number of shares underlying. Considering both positions, Robert’s exposure to the risk of the stock of the Michelin Group is: A. long. B. short. C. neutral. 答案之中有一句是“The exposure as a result of the short put position is also long.” 如何理解这种一句话?

老师，这道题原理不懂，老师可以帮忙解释下吗？ A country has high income, if the domestic income increase,which of the following will increase？ A.personal saving and investing B.trading balance C.financial balance

老师，有个题，大概意思是:一个供比赛的商家，有Pmatch＝9-0.2Qmatch。然后该商家每场比赛收4元，但大家认为这样增加了会员费。问题是:如果该商家继续保持比赛收费不变的话，会员费应该收多少？ A.62.5 B.162.5 C.40

老师，这题答案选A讲解说是选B，我觉得答案写错了，麻烦改一下吧