67. An equity manager conducted a stock screen on 5,000 U.S. stocks that comprise her
investment universe. The results of the screen are presented in the table below.
Criterion % of Stocks
Meeting Criterion
Price per share/Sales per share <1.25 35.0
Total asset/Equity ≤ 2.5 48.2
Dividends >0 58.6
Consensus forecast EPS >0 75.0
Meeting all 4 criteria simultaneously 10.8
If all the criteria were completely independent of each other, the number of stocks
meeting all four criteria would be closest to:
A. 293.
B. 371.
C. 540.
为什么计算“the number of stocks meeting all four criteria ”用的是0.35 x 0.482 x 0.586 x 0.75 = 0.074或7.4%,而不能用表格中直接给出的10.8%。两者的区别究竟在哪里?请牛牛们指点一下
他说了4个条件是independent,可现实中他们有关联性,所以跟实际比率会不一样。
比如说dividend>0的公司,eps 大于0的概率就会大于75.0%,这样就不能算completly independent. indepedent的概念是,dividend>0的集合里,跟dividend=0的集合里,eps>0的概率都是一样的,即75.0%.再细就没法说了,还请再看遍书吧。
嗯,我又重新读了读了题目,会不会题目的意思是这样,先给出了4个条件相互不一定独立的情况下,同时满足4个条件的比率是10.8%。
然后问假如4个条件相互独立的话,同时满足4个条件的比率又是多少。
也就是说,按照4个条件相互独立情况下计算出来的比率7.4%和题目给出的10.8%并不矛盾。他们只是在两种不同条件下的计算结果。
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