求助 OG(Purple)-Verbal-CR53

glaxosmith

There
is a great deal of geographical variation in the frequency of many
surgical procedures-up to tenfold variation per hundred thousand people
among different areas in the numbers of hysterectomies,
prostatectomies, and tonsillectomies.

To support a conclusion
that much of the variation is due to unnecessry surgical procedures, it
would be most important to establish which of the following?
A. A
local board of review at each hospital examines the records of every
operation to determine whether the surgical procesure was necessary.
B.
The variation is unrelated to factors (other than the surgical
procedures themselves) that influence the incidence of diseases for
which surgery might be considnered.
C. There are several categoreis
of surgical procedures(other than hysterctomies, prostatectomies, and
tonsillectomies)that are often performed unnecessarily.
D. For
certain surgical procedures, it is difficult to determine after the
operation whether the procedures were necessary or whether alternativev
treatment would have succeeded.
E. With respect to how often they
are performed unnecessarily, hysterectomies, prostatectomies, and
tonsillectomies are representative of surgical procedures in general.

Answer B
这道题目我一头雾水，请高人帮我分析一下。

YEWCHOW

题目说10万人中做....手术的频率区域性差别很大，问下面哪个选项的建立对得到差别来自于不必要的手术的结论最重要：

A说建立一个本地委员会来review和决定哪些不必要哪些必要的。每个地区不一样，本地委员会无法起到帮助，错。
B说证明差别和那些能影响这些需要手术的病的发生率无关。如果有关，每个地区的发病率不一样，就会导致题目提到的差别，与想得到的结论相悖。所以此选项是支持想得到的结论的，正确。
C说有好多其它的外科手术不必要。无关，错。
D对这几种手术来说，做完后很难说其是必要的，还是别的方法也能成功。不能判断必要和结论相矛盾，错。
E谈到是否经常没必要做的手术，这三个手术是具有代表性的。也是个结论，不是论据，错。

tracy214wxy

典型的排除他因。。。解释如下。

Conclusion: much of the variation is due to unnecessry surgical procedures => (not something else)
Premises: 1) great deal of geographical variation in the frequency of many surgical procedures

Support??

you want to find another piece of information that support that it is unnecessry surgical procedures that lead to big variation.

B) get rid of the possible other factors that might lead to the same outcome. no other factors are considered.

A) irrelevant. it does nothing to support the conclusion. it merely tells you a fact maybe.
C) irrelevant. we dont care about others.
D) irrelevant
E) again, irrelevant.