53. There is a great deal of geographical variation in the frequency of many surgical procedures-up to tenfold varition per hundred thousand people among different areas in the numbers of hysterectomies, prostatectomies, and tonsillectomies. To support a conclusion that much of the varition is due to unnecessary surgical procedures, it would be most important to establish which of the following? (B) The varition is unrelated to factor (other than the surgical procedures themselves) that influence the incidence of diseases for which surgery might be considered. 请问一下原题的意思是?? 答案B，为什麽跟这些考虑要动手术的因素无关呢??? OV详解看不太懂 麻烦大家了 谢谢!! --

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