NO.PZ2023010401000056
问题如下：
Which of the following statements concerning the Herfindahl–Hirschman Index (HHI) is most accurate?选项：
A.The HHI is a useful measure of potential barriers to entry. B.An HHI of 0.05 would be analogous to having the market shared equally by 20 firms. C.The HHI is usually unaffected by mergers among the top market incumbents.解释：
If there are M firms in the industry with equal market shares, the HHI equals 1/M. With 20 firms having equal shares, the HHI = 1/20 = 0.05.
中文解析：
如果行业中有M家公司拥有相等的市场份额，则HHI等于1/M。如果20家公司的股份相等，HHI = 1/20 = 0.05。
不是说要把百分号去掉再计算吗？那就应该是5^2*20=500啊？
