请教OG-172

Sedulously

172. There is a great deal of geographical variation in the frequency of many surgical
procedures—up to tenfold variation per hundred thousand between different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies.
To support a conclusion that much of the variation is due to unnecessary 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 procedure 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 considered.
(C) There are several categories of surgical procedure (other than hysterectomies, 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 alternative 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.
请问这道题目怎么理解啊,怎样的思路啊?感觉题目怪怪的,答案也不太理解
the key is B

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排除他因

daoying

Actually, this is a problem of assumption.As carefield said, the choice B rule out a posibility that it is disease-relatied factors rather than geographical variation that cause unnecessary surgical procedures and thus is an additional premise for the establishment of the conslusion.

hopr999

请牛牛把这道题翻译一下.

真的看不懂

missouyang

很多手术的变化频率各地差别很大----10万个H，P，D的手术，这个差别高达10倍。即某个地方的10万个手术中只有一种程序，都按一个程序去做，另一个地方却有10种不同程序，不同病因不同程序。