为什么是两个样本方差除一下就好了？

18.单选题 已收藏 标记 纠错 If there is no change in the proportion of each asset held in the portfolio or the expected standard deviation of the individual assets .The correlation between assets in a two–asset portfolio increases during a market decline will mostly cause the volatility of the portfolio to: A decrease. B remain the same. C increase. 查看解析 上一题 下一题 正确答案C 您的答案C本题平均正确率：75% Return measures, properties of returns难度：一般 推荐：      答案解析 Higher correlations will produce less diversification benefits provided that the other components of the portfolio standard deviation do not change (i.e., the weights and standard deviations of the individual assets). 问： 1.“If there is no change in the proportion of each asset held in the portfolio or the expected standard deviation of the individual assets .”这里用的是or，是否能理解为 权重和标准差都保持不变？ 2.market decline是干扰项吗？没用影响？

crp计算公式不是很理解，既然算的是股票市场的，为什么不直接用equity index of developing country而要把债牵扯进来?

15.单选题 已收藏 标记 纠错 Compared to investing in only one asset type, the portfolio of a risk–free asset and a risky asset has a better risk–return trade–off because the correlation between the risk–free asset and the risky asset is equal to A 0.0 B 1.0 C -1.0 查看解析 上一题 下一题 正确答案A 您的答案A本题平均正确率：70% Return measures, properties of returns难度：一般 推荐：      答案解析 portfolio of the risk–free asset and a risky asset or a portfolio of risky assets can result in a better risk–return trade–off than an investment in only one type of an asset, because the risk–free asset has zero correlation with the risky asset. 请问： 1.“because the risk–free asset has zero correlation with the risky asset.”这里的risky as set是EF上的任意一个点，还是整个坐标系内的任意一点？ 2.这个结论 即：Rf与任意一点的相关系数为0 ，可否解释一下（用图或者用公式） PS:请按问题顺序回答 谢谢

能给下T/S公式吗 我怎么没看懂 为什么还要两个比一下

discounted NCF那一列是怎么算出的，忘记了

这个案例中，对方公司不光安排了motel的住宿，并且安排了site-to-site的flight，但后面题目中并没有提到关于安排机票的信息，请问接受这样的交通安排不属于违规么？

请问： sharply distinguished 最大幅度的偏离和相关系数的关系可否画图表示？

老师，最上面这段话。convebiebce yield是说现在持有大宗商品的benfit，fp大于sp的情况下，因为未来价格涨，所以现在持有现货的benefit也高？啥意思？

A选项根据标答中的公式，感觉就是对的。B,C希望能进一步解释？