相关因果推理的一些困惑

Highway21Exit · 发表于 2015-5-14 15:41:07

GMAT批判性推理P118 Q4:
Medical researcher: as expected, records covering the last four years of ten major hospitals indicate that mothers who had received adequate care were less likely to have low birth weight babies than those mothers who had received inadequate prenatal care. Adequate prenatal care, therefore, significantly decreases the risk of low birth weight babies.

which of the following, if true, most seriously weakens the medical researcher's argument?

只贴出困惑项：
A. Mothers who give birth prematurely are routinely classified by hospital as having received inadequate prenatal care.
Helr 的解释是：原文翻译“那些孩子体重偏低的妈妈一般会被医院分到产前没有被照顾好的的那一类”。这个选项属于CQ3因果方向，即因为孩子体重偏低，所以被分类到产前没有照顾好的类别里。
我的解释：孩子体重偏低的妈妈会被医院分类为没有受到好的产前照顾这一类。这个事实说明研究者的结论是建立在人为bias上的，不可靠。
我的困惑：有没有照顾好应该是一个客观的评估，分类为没有受到好的照顾只能说是人为操作导致了评估不再客观（有了Bias，本来应该按客观条件分的，现在按孩子体重是否偏轻来分），和因果方向有什么关系？

D Women who receive adequate prenatal care are less likely to give birth prematurely than those women who do not receive adequate prenatal care.
Helr的解释：中文翻译：“相对于产前被照顾的不好的妈妈，哪些产前被照顾得很好的妈妈更不容易早产”。这个选项没有提及孩子体重偏低的问题，我们不能假设早产和体重偏低是等价的。
我的困惑：我以为早产导致体重偏低是一个生活常识，可以在GMAT里使用。这里说不能假设早产和体重偏低是等价，是不是意味着生活常识不可以用于GMAT？

还有一个地方很困惑，题目问the reasoning is most vulnerable to which option 和 which of the following most seriously weakens the argument有什么区别？

另外，实验类的题目，是否会有因为实验流程设计上有瑕疵导致结果不可靠？有的话，这道题应该怎么选？

ukyo2003 · 发表于 2015-6-6 11:11:21

能问一下OA是什么吗？我的理解如下：

GMAT批判性推理P118 Q4:
Medical researcher: as expected, records covering the last four years of ten major hospitals indicate that mothers who had received adequate care were less likely to have low birth weight babies than those mothers who had received inadequate prenatal care. Adequate prenatal care, therefore, significantly decreases the risk of low birth weight babies.
which of the following, if true, most seriously weakens the medical researcher's argument?
问题：观测事实：照顾得不好的孕妇生的孩子体重偏低。所以conclude，是照顾的质量决定生育的质量。考削弱。
逻辑链：1、任何导致孩子体重低的他因都可以削弱。2、直接削弱题设，医院的记录是错的

A. Mothers who give birth prematurely are routinely classified by hospital as having received inadequate prenatal care. (符合2，医院的记录是错的，医院自认为had received inadquate care的妈妈其实并没有被inadquate care，很有可能是别的疾病导致她们的孩子体重偏低)
D Women who receive adequate prenatal care are less likely to give birth prematurely than those women who do not receive adequate prenatal care. (加强)

alzn2765 · 发表于 2015-6-6 15:30:36

选A

A选项的意思就是说题干中的因果关系倒置了，不是因为“没受到足够的护理”，而导致“新生儿体重偏低”（果），而是因为“新生儿体重偏低”（因），才分到“没受到足够的护理的类别中”。
在相关性因果的推理中，因果倒置不会影响证据的正确性，也就是说不管是A导致B还是B导致A，都不妨碍“现象”的产生。

D选项明显是加强了。D就等于把结论重新说了一次的感觉。premature的baby一定是low weight，这个基本是“一般事实”，没有异议。

相关性因果中削弱的方向基本就两个：A与B没有相关性，因果倒置。

攒人品，希望有人回答我的问题：
http://forum.chasedream.com/thread-1009949-1-1.html

不一样的刘二傻 · 发表于 2017-7-11 04:02:54

同问：原文中说的是mothers who give birth prematurely, 而早产儿并不一定体重低吧。
看到毕出老师的解释中已经默认mothers who give birth prematurely 为体重偏低的母亲。

而B选项说的是： The hospital records indicate that low birth weight babies were routinely classified as having been born prematurely.
我觉得这个选项可以称之为一个独立第三因素啊，因为早产所以体重低并不是因为孕妇照顾不周。有效的weaken
求各位NN 解答
多谢~

[Helr题库] 相关因果推理的一些困惑

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