og12 114 求一个小确认~~~小菜抱拳啦~~~~~！！！！

bob9603

114. Guidebook writer: I have visited hotels throughout thecountry and have noticed that in those built before1930 the quality of the original carpentry work isgenerally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930typically worked with more skill, care, and effort thancarpenters who have worked on hotels built subsequently.[c1]

Which of the following, if true, most seriously weakens the guidebook writer’s argument?



(A) The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.[c2]

(B) Hotels built since 1930 can generallyaccommodate[c3] more guests than those built

before 1930.

(C)[c4] The materials available to carpenters workingbefore 1930 were not significantly different inquality from the materials available tocarpenters working after 1930.

(D)[c5] The better the quality of original carpentry in a building, the less likely that building is to fall intodisuse and be demolished.D

(E)[c6] The average length of apprenticeship forcarpenters has declined significantly since 1930[c1]因果型结论


[c2]无关


[c3]没有信息说明其与木工质量的关系


[c4]Support


[c5]显示导致因果的资料有误。说明用现存的hotel做比较不具有代表性，因为很可能过去很多质量不好的都弃用了，剩下的都是好的。


[c6]Support

我不是很明白，是说原文结论的结论有误，取而代之的应该是和质量有关的D吗？？？也就是D中所说的质量越好，越少demolished~是这个意思吗？也就是weaken题常用的给出的信息不正确，是这个意思吗？即才c1处是错的，weaken的就是这个~

刚果弯弯

babybearmm 发表于 2012-4-15 11:16
Exactly        Survivorship biasUsually pertaining to fund manager or  ...

大神nn 可否解答一下为什么b中的 可以accommodate more不能代表其质量更好呢？ 质量不好又怎么能accommodate more呢？

刚果弯弯

ainiAnnie 发表于 2012-3-8 12:28
我的思路如下，欢迎讨论1. 读题，第一句话data，作为premise。第二句话conclusion，标志"clearly"2. dia ...

如果非要说accomodate more不代表质量好 我也可以说老房子被拆毁是因为外表太老太丑了不是因为质量不好啊？

刚果弯弯

ainiAnnie 发表于 2012-3-8 12:28
我的思路如下，欢迎讨论1. 读题，第一句话data，作为premise。第二句话conclusion，标志"clearly"2. dia ...

nn 可否解答一下为什么b中的 可以accommodate more不能代表其质量更好呢？

Victoriagirl

看完此帖后，原来逻辑需要系统的复习，理清经脉，找出各个解决问题的方法，好好努力吧！baby姐大神啊

babybearmm

Exactly

        Survivorship bias
Usually pertaining to fund manager or individual investor performance. Suppose we examined the performance over the last ten years of a group of managers that exist today. This performance is biased upwards because we are only considering those that survived for 10 years. That is, some dropped out because of poor performance. Hence, in evaluating performance, one has to be careful to include both the current and the managers that dropped out of the sample due to poor performance.
Copyright © 2011, Campbell R. Harvey. All Rights Reserved.
Survivorship Bias
In finance, the tendency to exclude failed companies or managers from performance evaluations or studies simply because they do not exist. Survivorship bias can result in skewed findings in a study and lead a casual reader to believe that a study shows a rosier picture than it really does. Mutual funds, especially smaller ones, are especially susceptible to survivorship bias. At any given time, 90% of mutual funds will claim to be in the top 25% of performers. Technically, they are correct, but only because the other 75% have closed or merged. Manager universe comparisons have also been criticized for exhibiting signs of survivorship bias. It is also known as survivor bias.
Farlex Financial Dictionary. © 2011 Farlex, Inc. All Rights Reserved

bob9603

BABY姐的分析又是这么到位！
不过我还有一个疑问，题目中说的质量不好的会被拆除，那只是针对1930年以前的建筑而言么？现在所看到的1930之后的建筑就不是留下的最好的？

-- by 会员 tthere (2012/4/13 15:57:13)

按照survivorship bias去理解哦。现存的建筑，都是经得起历史折腾的，1930年以前的建筑经受的历史风雨更多，因此能保存到现在的，肯定是质量好的。
数学上表述，survival rate (y)和time (x)的函数，是下降，然后趋于平滑的，趋近于y=0

类似的surviorship bias的例子非常常见，比如说：
你想研究某个factor (e.g.investment on R&D)对某类公司(e.g. Biotech)的某个指标（例如股价）的影响，你的研究方法是从现有NYSE的biotech sector中挑选历史至少5年的公司作为samples，对每个sample分别研究其历史变化规律。
那么，这项研究就存在survivorship bias，因为你只考虑到了现存的公司，你的样本中没有考虑这5年内倒闭的公司。这样一种sampling bias会对你的结果造成影响。

-- by 会员 babybearmm (2012/4/15 3:06:40)

baby姐，我特意查了一下survivorship bias的中文意思，大概意思是：存活者偏差~（网络释义~）
那也就是说，原文认为出现现象的原因是质量~
而实际上，应该是时间问题，即，一个经历了long time 才留下来；另一个才只是现在时的东西~
通俗一点说：虽然都“活着”，但活了多久的是不一样的~而D间接的说出了由于时间问题而导致的“存活”现象~

是这个意思吧baby姐~

babybearmm

BABY姐的分析又是这么到位！
不过我还有一个疑问，题目中说的质量不好的会被拆除，那只是针对1930年以前的建筑而言么？现在所看到的1930之后的建筑就不是留下的最好的？

-- by 会员 tthere (2012/4/13 15:57:13)

按照survivorship bias去理解哦。现存的建筑，都是经得起历史折腾的，1930年以前的建筑经受的历史风雨更多，因此能保存到现在的，肯定是质量好的。
数学上表述，survival rate (y)和time (x)的函数，是下降，然后趋于平滑的，趋近于y=0

类似的surviorship bias的例子非常常见，比如说：
你想研究某个factor (e.g.investment on R&D)对某类公司(e.g. Biotech)的某个指标（例如股价）的影响，你的研究方法是从现有NYSE的biotech sector中挑选历史至少5年的公司作为samples，对每个sample分别研究其历史变化规律。
那么，这项研究就存在survivorship bias，因为你只考虑到了现存的公司，你的样本中没有考虑这5年内倒闭的公司。这样一种sampling bias会对你的结果造成影响。

babybearmm

这题又被Re出来了啊.....
要我现在看，之前我写的思路太繁琐。这题就一典型的survivorship bias.
survivorship bias is perhaps the most common type of sampling bias.
了解这个，类似题目就举一反三了。

亲亲麦小兜

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