NO.PZ2016010802000078
问题如下：
An analyst gathered the following market share data for an industry comprised of five companies:
The industry’s three-firm Herfindahl-Hirschmann Index is closest to:
选项：
A.
0.185.
B.
0.225.
C.
0.235.
解释：
B is correct.
The three-firm Herfindahl-Hirschmann Index is
0.35^2+0.25^2+0.2^2=0.225
考点：Herfindahl-Hirschmann Index
解析：本题较为常规，直接选取排名前三家公司的数据，带入公式计算即可。0.35^2+0.25^2+0.2^2=0.225
为什么选取前三家公司不是前四家或者前五家？
