求助一道manhattan模考的CR

123SherryGo

Child development specialists have observed that adolescents who receive large weekly allowances tend to spend money on items considered frivolous by their parents whereas adolescents who receive small weekly allowances do not. Thus, in order to ensure that their children do not spend money on frivolous items, parents should not give their children large weekly allowances.
Which of the following pieces of information would be most useful in evaluating the validity of the conclusion above?


(A) The average amount of money received by adolescents who receive large weekly allowances
(B) Any differences among parents in the standard used to judge an item as frivolous
(C) The educational background of the child development specialists who made this observation
(D) The difference between the average annual income of families in which the parents give their children large weekly allowances and that of families in which the parents give their children small weekly allowances
(E) The percentage of adolescents who receive no weekly allowance


我是根据Helr的方法做，判断这道题应该是相关因果，我感觉这道题BC的评估方向一致，不知道怎么排除。


答案在二楼。

123SherryGo

OA:B

附上manhattan的解释

The conclusion of the passage is that parents can ensure that their children will not spend money on frivolous items by limiting their children's allowances. This claim is based on the observed difference between the spending habits of children who receive large allowances and those of children who receive small allowances. The argument assumes that the high dollar amount of the allowance – as opposed to some other unobserved factor – is directly linked to the fact that children spend the money on items their parents consider frivolous. Information that provides data about any other factor that might be the cause of the children's spending behavior would help to evaluate the validity of the conclusion.
(A) The actual dollar amount received by adolescents who receive large weekly allowances is not related to the conclusion of the passage. Whether this amount is $40 or $10, the key is that it is considered by the child development specialists to be a "large" weekly allowance.
(B) CORRECT. One alternative to the conclusion of the passage is that the standard used to judge an item as frivolous was much lower for parents who gave their children large weekly allowances than for parents who gave their children small weekly allowances. If for example, the former group of parents considered all movie tickets to be frivolous, while the latter did not, then this fact (and not the difference in allowance money) might explain the difference observed by the child development specialists. Thus, information about any differences among parents in the standard used to judge an item as frivolous would be extremely relevant in evaluating the validity of the conclusion of the passage.
(C) The background of the child development specialists who made the observation has no bearing on the conclusion. The conclusion is based on the observation, not on the credentials of those making the observation.
(D) Family income differences have no clear relevance to the link posited between high allowances and spending on frivolous items.
(E) Adolescents who receive no weekly allowance play no role in the argument. Thus, information about this group of adolescents has no relationship to the conclusion of the passage.

123SherryGo

自己顶顶！！！求NN啊

123SherryGo

不知大牛们都什么时候出没

cycgundam

偶尔看到这道题，说说自己思路（我是在搜manhattan GMAT的资料）：

Adolescents在这个逻辑题里有两种。一种家长们认为每月拿很多零花钱的adolescents在frivolous上花了很多钱，另一种零花钱拿的少的则是花了很少钱。结论：为了避免adolescents在frivolous上面花钱太多，家长应该少给零花钱。题目问：选择一条有用信息来评估这个题目逻辑的合理性。

那么选项必须产生两种效果，正即支持题目逻辑；反则削弱题目逻辑。

A）那些adolescent在frivolous上花大钱的具体数目。该选项和题目的逻辑合理与否无关。文章已经告诉你这些adolescent花钱很多，具体花了多少并不重要。一般这种过于扩展逻辑中依据的选项很少会是正确选项。该扩展的部分一般是逻辑的设想（assumption）部分。

B）家长评判frivolous的标准。这个选项是正确的，比如给adolescent零花较少的家长极有可能在frivolous上评判标准与给adolescent零花较多的家长不一致。如果不一致，frivolou就没有了统一的标准，那基于此的结论就是站不住脚的；如果意见一致，那至少就题目给出的有限信息来看，结论还不至于被有效驳斥。

C）组织评估员的教育背景与逻辑题无关。这个评估员的教育程度可以很高，可以很低，然而很高或很低是否会影响文章结论？这点信息没有给与。个人以为GMAT逻辑题的忌讳之处就是虽然我们选择的“设想”很主观，但越基于文章给出的信息，正确合理性越高。如果离越远，比如在设想上再建立设想使其与题目逻辑有联系，那么这个选项就是错误的。

D）给零花钱的家庭收入差异。这点其实很接近，但是还不够接近，所以它和命题的逻辑还是有代沟。家庭收入不管高还是低，关键信息-给adolescent的零花钱数量不会被动摇，基于这个信息的结论（无论对错与否）都不会受到影响。如果题目中所谓的large allowance改成allowance based on house income percentage，那么这个选项或许会很接近。

E）没收到零花钱的adolescents百分比。命题结论完全与此无关，故而忽略。