NO.PZ2015122802000043
问题如下：
An analyst gathers the following information for an equal-weighted index comprised of assets Able, Baker, and Charlie:
The price return of the index is:
选项：
A.
1.7%.
B.
5.0%.
C.
11.4%.
解释：
B is correct.
The price return is the sum of the weighted returns of each security. The return of Able is 20 percent [(12 – 10)/10]; of Baker is –5 percent [(19 – 20)/20]; and of Charlie is 0 percent [(30 – 30)/30]. The price return index assigns a weight of 1/3 to each asset; therefore, the price return is 1/3 × [20% + (–5%) + 0%] = 5%.
考点：Methods of index construction
这道题让我们计算的是等权重构建方法下的指数的price return，所以我们首先要区分price return和total return，计算price return不需要包括期间的收益即股息。第二，这里是等权重的构建方法，等权重相当于每只股票买了相同的金额，那么我们就先计算每种股票的收益率再除以股票种类。
跟三个end加起来减去三个begin除以三个begin有什么区别
