Suppose that finishing in the top half of all portfolio managers is purely luck, and that the probability of doing so in any year is exactly ½.  Then the probability that any particular manager would finish in the top half of the sample five years in a row is (½)5 = 1/32.  We would then expect to find that [350 ´ (1/32)] = 11 managers finish in the top half for each of the five consecutive years.  This is precisely what we found.  Thus, we should not conclude that the consistent performance after five years is proof of skill.  We would expect to find eleven managers exhibiting precisely this level of "consistency" even if performance is due solely to luck.
谢谢各位达人啦，这是一道投资学的题得英文答案哦能不能帮小弟翻译下下，谢谢哦