GWD17-Q30

Justin12122

Q30:

In a study conducted in Pennsylvania, servers in various restaurants wrote “Thank you” on randomly selected bills before presenting the bills to their customers. Tips on these bills were an average of three percentage points higher than tips on bills without the message. Therefore, if servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been.

Which of the following is an assumption on which the argument relies?

1. The “Thank you” messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant.
2. Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits.
3. The written “Thank you” reminds restaurant patrons that tips constitute a significant part of the income of many food servers.
4. The rate at which people tip food servers in Pennsylvania does not vary with how expensive a restaurant is.
5. Virtually all patrons of the Pennsylvania restaurants in the study who were given a bill with “Thank you” written on it left a larger tip than they otherwise would have.

我选A，答案是B，

可是B中的revert to their earlier tipping habits说的很不好。earlier tipping habits指的是什么？既然说的是Habits,也就是在某种情况的限制下他们不假思索所采取的行动。而这某种情况的限制就是每道菜都写thank you。那么之前做的调查显示，写thank you的有一部分菜人们就会多给tips，那我完全可以把“写thank you的有一部分菜人们就会多给tips”理解为是一种habit，这样的话，对B取非就是加强了~~。

所以还是选A.  A能起到是搭桥作用。

[此贴子已经被作者于2009/7/17 19:28:31编辑过]

salad1989

这道题目我也做错了，我选的D，逻辑题我一般靠感觉，所以说不上来选或不选的原因

vivian128

?

美小波

顶下~~

我选D。。。

很不明白B的答案对哪儿。。。 请教~~

konell

A我觉得把客人硬性分类就不对了，A相当于自己又假设了regular patrons ，occasional patrons两者付小费不同了，孰多孰少呢又？

B正确在于，排除了revert to their earlier tipping habits这个可能，使 seeing “Thank you” written on their bills ，能达到 average income from tips would be significantly higher than it otherwise would have been这个目的。

D 又画蛇添足的把restaurant自己假设分个expensive or not类，没有意义。

yanlingli31

题干是先做了个实验，实验的结果是bill上有thank you的那些账单tip多，结论是，如果账单上都加上thank you，那么tip会比没有thank you的时候多。

可是B能算做一个假设吗？如果B不对，那实验的结果是怎么出来的呢？实验就已经说明了加了thank you后客人给得多，也就是不像以前那么给tip呀。没有B结论也成立呀。

faridahchen

我的理解是,题目的结论是写"thank you"就能够增加小费的数量,所以前提要达到的效果是:老看到"thank you"不会导致小费不增加 .
A错,因为就算不常来的客人不会像常来的客人那样多给小费,小费还是会增加
D错,因为就算给的小费的增加比例不一样,小费还是增加了
B项满足了"小费不会不增加"的要求,因此是对的.

hezijun

对假设题的正确选项取非，则使结论必不成立的原则，我们看B：如果thank you这个举动将导致客人回归原来的付小费的习惯（原来的tips较现在少），那么tips增加这个结论必然不成立。
再看A、D，对题干取非，就算thank you的效果因不同种类顾客或不同种类餐馆有所不同，但总体而言，仍使得小费总额增加，结论最多被削弱但仍可能成立。

grace1210

写有thank you的bill，消费者给的小费比没有写Thank you 的bill平均高出了3%。

结论：如果经常写Thank you，那么服务员从小费中得到的工资会增高。

但是如果服务员经常写Thank you，而消费者看厌了而不多给些费了呢？所以要想使得工资增高，那么必须假设经常写Thank you不会改变原来实验的结果-----消费者仍然给高出3%的小费。

D中，expensive与否与题目中强调的regularly无关。所以错了

louishirley

根据lawyer对题型和解法的分类，这题的结论是充分必要类型，所以assumption要么对前提进行保护，充分一定推出必要；要么排除充分条件出现，没有必要条件的情况。

Conclusion：if servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been.

B项：Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits。满足第二种情况，排除充分条件出现，必要条件不存在。实际上就是对该选项取非可以weaken结论。