吴超 Cassie · 2021年12月21日
NO.PZ2015120604000124
问题如下：
If an analyst uses a sample of historical data for analysis. But at the time being analyzed, the data was not open.Wha kind of this bias is?
选项：
A. look-ahead bias.
B. sample selection bias.
C. time-period bias.
解释：
A is correct.
Option C defines the look-ahead bias which was created by using the data that would not have been available .
本题种所研究的数据属于当前不可得的，为Look-ahead bias的表现。
这题好奇怪，既然是历史数据，那为啥又not open ，如果是not open，那这数据又是哪儿来的？
NO.PZ2015120604000124问题如下 If analyst uses a sample of historicta for analysis. But the time being analyze the ta wnot open.Wha kinof this biis?A.look-ahebias.B.sample selection bias.C.time-periobias. A is correct.Option C fines the look-ahebiwhiwcreateusing the ta thwoulnot have been available .本题种所研究的数据属于当前不可得的，为Look-ahebias的表现。 都有哪些偏差呢，各自特点是什么。辛苦告知基础班讲义位置就可以，能直接截个图就更好了谢谢。
NO.PZ2015120604000124问题如下If analyst uses a sample of historicta for analysis. But the time being analyze the ta wnot open.Wha kinof this biis?A.look-ahebias.B.sample selection bias.C.time-periobias. A is correct.Option C fines the look-ahebiwhiwcreateusing the ta thwoulnot have been available .本题种所研究的数据属于当前不可得的，为Look-ahebias的表现。 啥叫the ta is not open? 从没见过这种表述。。。
有些搞不明白，为什么历史数据不可得呢？都用了历史数据，不是就说明是可以找到的吗？
问一道题：NO.PZ2015120604000124 [ CFA I ]
