问题如下图：
选项：
A. 
B. 
C. 
解释：
能解释下答案意思吗？不太明白和公式关系在哪
Shimin_CPA税法主讲、CFA教研 · 2018年10月18日
我直接解释答案哈。首先这道题问的是n个equal weighted的资产做组合，所以可以写出答案中的这个公式，这个公式要记住的。
公式等号后面有两个因素，variance & covariance，由于1/n+(n-1)/n=1，所以1/n与(n-1)/n可以看作是这两个变量的权重。
题目问的是如果n增加，variance还是covariance对组合的方差有更大的贡献度，也就是问哪个权重更大。那么由于n增加，1/n减小，(n-1)/n增加，所以variance的权重会更小，covariance的权重会更大一些。所以选B。
NO.PZ2018070201000063问题如下Eunice, analyst from investment company, recently ma the following statements:Statement 1: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio increase;Statement 2: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio crease;Statement 3: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio remains the same.Whistatement is most correct?A.Statement 1.B.Statement 2.C.Statement 3.B is correct.the number of assets in the same weighting portfolio increases, the contribution of eainviasset's contribution to portfolio volatility creases. the number of assets in equally weighteportfolio increases, the contribution of co-movement measures between assets increases. The following equation for the varianof equally weighteportfolio illustrates these points:σρ2=σ¯2N+N-1NCOV¯=σ¯2N+N-1Nρσ¯2N越大，相关系数越小，分散化越好
NO.PZ2018070201000063问题如下 Eunice, analyst from investment company, recently ma the following statements:Statement 1: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio increase;Statement 2: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio crease;Statement 3: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio remains the same.Whistatement is most correct?A.Statement 1.B.Statement 2.C.Statement 3.B is correct.the number of assets in the same weighting portfolio increases, the contribution of eainviasset's contribution to portfolio volatility creases. the number of assets in equally weighteportfolio increases, the contribution of co-movement measures between assets increases. The following equation for the varianof equally weighteportfolio illustrates these points:σρ2=σ¯2N+N-1NCOV¯=σ¯2N+N-1Nρσ¯2根据公式，随着数量的增加也就是可以理解成n增大，用极限的思想看，当N趋近于无限大时，1/N趋近于0，N-1/N趋近于1，也就是整个公式只会受COV的影响，题目给出的条件并不影响COV，为什么不是不变呢，我这个理解有什么问题吗
这个里的公式不是假设stanrviation same 吗？和B是否矛盾？这如何理解B
这道题不明白考的是哪个点？用答案里的多资产计算公式我觉得也和这道题说的单个资产对组合影响程度无关呢？