求助GWD-17-Q30 老的讨论贴没有找到

 GWD17-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?

A-B

A.      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.

B.       Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits.

C.      The written “Thank you” reminds restaurant patrons that tips constitute a significant part of the income of many food servers.

D.      The rate at which people tip food servers in Pennsylvania does not vary with how expensive a restaurant is.

E.       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.

 B选项不大明白~望大家指点

这个问题有意思，我还碰到过一个在BILL上附信用卡品牌的题， 哈哈。

来说这个，  原文作者想得出的观点是， 一次性的统计规律可不可以延续。  也就是一次消费增多会不会以后经常增多。

选项A 是错的，  它误导我们认为一次性的统计是针对于一次性顾客，经常统计是针对于经常顾客， 而事实上，什么时候的顾客群都是包含二者的，所以这样的选项对评价观点一点贡献也没有， 无关。

选项B 就对了，  说不会存在这么一种情况，顾客常看到这个THANK YOU就看烦了， 回到原来的低小费习惯。  这就是假设， 如果此情况存在，原作者观点大大削弱。 所以，把这种情况的可能性封锁掉，就是假设