GWD-10-Q29 & GWD-2-14 的疑问，请牛人相助！

GWD-10-Q29：GWD-2-14
                

Smithtown
                University’s fund-raisers succeeded in getting donations from 80 percent of the potential donors they contacted.  This success rate, exceptionally high for university fund-raisers,
                does not indicate that they were doing a good job.
             On the contrary, since the people most likely to donate are those who have donated in the past, good fund-raisers constantly try less-likely prospects in an effort to expand the donor base.  The high success rate shows insufficient
                canvassing effort.

Which of the following, if true, provides more support for the argument?

A.      Smithtown
                University’s fund-raisers were successful in their contacts with potential donors who had never given before about as frequently as were fund-raisers for other universities in their contacts with such people.

B.       This year the average size of the donations to Smithtown
                University from new donors when the university’s fund-raisers had contacted was larger than the average size of donations from donors who had given to the university before.

C.      This year most of the donations that came to Smithtown
                University from people who had previously donated to it were made without the university’s fund-raisers having made any contact with the donors.

D.      The majority of the donations that fund-raisers succeeded in getting for Smithtown
                University this year were from donors who had never given to the university before.

E.   More than half of the money raised by Smithtown
                University’s fund-raisers came from donors who had never previously donated to the university.

答案是a。

疑问：本题的结论是does not indicate that they were doing a good job.  这句话有2个理解：1.他们没有工作好。2.不能推出他们是否工作好了。

但是从选项a，1.我们显然不能推出他们不成功，因为“和别的大学一样”的一个比例显然不能推出成功或者不成功。

                      2.文章中的“80%”这句暗含了一个意思：数据本身可以反映游说人员的成功与否，只要数据本身无可争议。由于游说人员的2个方面的成功率都“已知”了：（1）以前捐款过的，“很高”。（2）以前没捐款过的，“和别的大学的比例一样高”或“用总数和成功率（1）算出”。这样一来无论成功率（2）高低，只要这个成功率能确定，就能判断游说是否成功。

从A当然可以推出这个人是不成功的，从success rate可以看出80%这个概率比其他学校的概率都要高，A说这个人在游说原先没有捐过款的人来捐款的成功频率和其他学校的人是一样的，我们可以假设一个公式总success rate=a*游说没捐过的rate+b*游说捐过的rate（a和b是权数）那么当第一格rate全相同的时候，总rate的高高在上就可以归结于对于捐过款的人的游说，说明他在这方面的工作做的多，也就是文中所说的insufficient
                canvassing effort

谢谢ls解答。

但是80%能推出这个率比别的学校的都要高吗？万一大家都“高”呢。

比如一个篮球队，我们见到了说“你们都很高”，虽然他们之间相比还是有高矮的。

e，顶顶，有好心人解答困惑么..