OG-114，求大牛解释@@@！！！

pye348789

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 builtsubsequently.
Which of the following, if true, most seriously weakensthe guidebook writer’s argument?
(A) The quality of original carpentry in hotels isgenerally far superior to the quality of originalcarpentry in other structures, such as housesand stores.
(B) Hotels built since 1930 can generallyaccommodate more guests than those builtbefore 1930.

(C) The materials available to carpenters workingbefore 1930 were not signifi cantly different inquality from the materials available tocarpenters working after 1930.
(D) The better the quality of original carpentry in abuilding, the less likely that building is to fall intodisuse and be demolished.
(E) The average length of apprenticeship forcarpenters has declined signifi cantly since 1930.

我还是不懂啊。。
1. D选项中的质量差的房子容易被损坏并没有特指1930前的房子吧，也有可能指的是1930年后的房子啊。。
2. 就算质量差的房子容易损坏，就一定能推出————————1930年前有大量质量差的房子了？这是什么逻辑啊

Quadrifolia

这道题的逻辑是：1930年前的木匠比1930年后的木匠更优秀→1930年前的宾馆

original carpentry work 的质量要优于1930年后的。问削弱，答案即因为其他原

因导致的这个结果。
D选项： original carpentry的质量越高，就越不容易废弃和损坏。楼主可以这么

理解，1930年前后的木匠技术都是一样的，制作出来的木制品都很优秀。但是因为

1930年前的原始木料质量要好，所以保存下来比1930年后的要完整，而1930年后的

大多已经废弃和损坏了，这个writer就误认为是因为木匠手艺的原因导致的。

解释的比较通俗，希望楼主能看懂

pye348789

我能理解 这样的解释，可是，您说的那句但是因为1930年前的原始木料质量要好，所以保存下来比1930年后的要完整，而1930年后的大多已经废弃和损坏了 这个是从哪里得出来的啊？

难道GMAT 需要引申那么远吗？

vernetta

Weakening a statement does not require proving it wrong.  All it needs is to shed an unfavorable light on the statement and make the statement less likely.

JUNO1031

Statistically speaking, this study has so-called survivorship bias - the most common form of sample selection bias.

from wiki:

Survivorship bias is the logical error of concentrating on the people or things that "survived" some process and inadvertently overlooking those that didn't because of their lack of visibility. This can lead to false conclusions in several different ways. The survivors may literally be people, as in a medical study, or could be companies or research subjects or applicants for a job, or anything that must make it past some selection process to be considered further.

Survivorship bias can lead to overly optimistic beliefs because failures are ignored, such as when companies that no longer exist are excluded from analyses of financial performance. It can also lead to the false belief that the successes in a group have some special property, rather than being just lucky. For example, if the three of the five students with the best college grades went to the same high school, that can lead one to believe that the high school must offer an excellent education. This could be true, but the question cannot be answered without looking at the grades of all the other students from that high school, not just the ones who "survived" the top-five selection process.

Survivorship bias is a type of selection bias.