NO.PZ2022062760000015
问题如下：
A modeling team at a risk management consulting firm is debating whether it is appropriate to use the
bootstrap technique to analyze a particular sample of data. Which of the following represents a situation
where the bootstrap technique will be ineffective?
选项：
A.
The data follow an asymmetric distribution.
B.
The data are independent and identically distributed.
C.
The data contain outliers.
D.
The data are normally distributed.
解释：
中文解析：
C 是正确的。至少有两种情况会导致 bootstrap 无法正常工作：数据中是否存在异常值，以及数据是否相互依赖。
A 不正确。 bootstrap 的一个好处是它们没有分布要求——bootstrap 不关心数据来自什么分布。
B 不正确。恰恰相反，数据必须独立才能使引导程序有效。
D 不正确。对 A 的相同解释在这里适用。
C is correct. There are at least two situations where the bootstrap will not work well: if there are outliers in the data, and if the data are dependent on one another.
A is incorrect. One benefit of the bootstrap is the fact that they do not have distributional requirements – the bootstrap does not care what distribution the data come from.
B is incorrect. The very opposite is true, data must be independent in order for the bootstrap to be effective.
D is incorrect. The same explanation for A applies here.
什么是bootstrap 可以解释一下吗？
