[求助]GWD 20-27 要考试了 急！

就要考试了，急啊~ 这题没看懂，大家帮忙解释一下 谢~

Q27:

A significant number of complex repair jobs carried out by Ace Repairs have to be reworked under the company’s warranty.  The reworked jobs are invariably satisfactory.  When initial repairs are inadequate, therefore, it is not because the mechanics lack competence; rather, there is clearly a level of focused concentration that complex repairs require that is elicited more reliably by rework jobs than by first-time jobs.

The argument above assumes which of the following?

1. There is no systematic difference in membership between the group of mechanics who do first-time jobs and the group of those who do rework jobs.
2. There is no company that successfully competes with Ace Repairs for complex repair jobs.
3. Ace Repairs’ warranty is good on first-time jobs but does not cover rework jobs.
4. Ace Repairs does not in any way penalize mechanics who have worked on complex repair jobs that later had to be reworked.
5. There is no category of repair jobs in which Ace Repairs invariably carries out first-time jobs satisfactorily.

   Answer:  A

XDJM大家帮帮忙哦~~~~

就是说，有一项修理工作需要这个公司完成，可他们做的不好，要返工。返工的产品合格了。于是分析原因说，返工比头一次做得好是由于concentration--即工人们比较重视和注意了。

如何体现工作成果的提高只是由于重视程度的提高？那就要排除其他原因（ceteris paribus)。

所以选项A中的假设：第一和第二次完成工作的工人基本是同样的。no systemetric difference in membership 就是为了强调两次完成工作的工人的相同点。