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标题: 求助OG紫色53题 [打印本页]

作者: crystalvine212    时间: 2010-3-9 00:13
标题: 求助OG紫色53题
53There 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 unnecessary surgical proceduresit 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 prostatectomiesand tonsillectomies)that are often performed unnecessarily
(D)For certain surgical proceduresit 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, hysterectomiesprostatectomiesand tonsillectomies are representative of surgical procedures in general

答案是B
作者: hughlv    时间: 2010-3-9 09:34
倒推一下逻辑:

题干:不同地区的相同基础人群中手术比例非常不同
结论:有很多手术是没必要的
推导:假如一个地区的人得某病的概率要远大于另一个地区,那么这个地区做这类手术的比例自然应该高一些。因此为了能得出结论,必须证明这个假设不成立,或者假设与结论之前不存在直接的联系。B就是这个意思了。

CDE比较容易排除,我倒是多看了会A,但是确实它不是很关键的原因。




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