GWD21-Q4求解答，没有讨论过的

rainnight

Whichof the following most logically completes the passage?

Appendicitis(inflammation of the appendix) is potentially fatal; consequently, patientswith symptoms strongly suggesting appendicitis almost always have theirappendix removed.  The appropriatesurgery is low-risk but performed unnecessarily in about 20 percent of allcases.  A newly developed internal scanfor appendicitis is highly accurate, producing two misdiagnoses for every 98correct diagnoses. Clearly, using this test, doctors can largely avoid unnecessary removalsof the appendix without,however, performing any fewer necessary ones than before, since______.

A.    thepatients who are correctly diagnosed with this test as not having appendicitisinvariably have medical conditions that are much less serious than appendicitis
B.     themisdiagnoses produced by this test are always instances of attributingappendicitis to someone who does not, in fact, have it
C.    allof the patients who are diagnosed with this test as having appendicitis do, infact, have appendicitis
D.    everypatient who is diagnosed with this test as having appendicitis has more thanone of the symptoms generally associated with appendicitis
E.     theonly patients who are misdiagnosed using this test are patients who lack one ormore of the symptoms that are generally associated with appendicitis
完全不明白为什么选Ｂ，请ＮＮ现身解答。。

FGHYU19912301

把B选项中的in fact去掉，意思就好理解多了the misdiagnoses produced by this test are always instances of attributing appendicitis to someone who does not have it，这种新测试方法的误诊，就是把那些没有得阑尾炎的人判成阑尾炎。
结合文章的信息，这种无中生有的误诊率在2%一下，大大低于原来的20%，并且绝不会漏掉真正得了阑尾炎的人，因而支持文章的结论：避免了不必要的手术，不影响得了阑尾炎，需要做手术的人。

slmne

我是这么想的

Appendicitis(inflammation of the appendix) is potentially fatal; consequently, patientswith symptoms strongly suggesting appendicitis almost always have theirappendix removed.  The appropriatesurgery is low-risk but performed unnecessarily in about 20 percent of allcases.  A newly developed internal scanfor appendicitis is highly accurate, producing two misdiagnoses for every 98correct diagnoses. Clearly, using this test, doctors can largely avoid unnecessary removalsof the appendix without,however, performing any fewer necessary ones than before, since______.

LZ你已经划出了结论，也就是这个stimulus的关键，就是说: 这个new test是个好东西，可以更能避免不必要的误诊

A.    thepatients who are correctly diagnosed with this test as not having appendicitisinvariably have medical conditions that are much less serious than appendicitis==>说的是patient的病体情况和结论关于这个test的没有关系，所以是irrevalent
B.     themisdiagnoses produced by this test are always instances of attributingappendicitis to someone who does not, in fact, have it==>说这个test的正确性，和结论有关，放着
C.    allof the patients who are diagnosed with this test as having appendicitis do, infact, have appendicitis==>说这个test的正确性，和结论有关，放着

D.    everypatient who is diagnosed with this test as having appendicitis has more thanone of the symptoms generally associated with appendicitis==>同A的错误，无关
E.     theonly patients who are misdiagnosed using this test are patients who lack one ormore of the symptoms that are generally associated with appendicitis==>这个选项看似有关其实无关，相当于shell game的选项，因为最后说的是patients who lack one ormore of the symptoms that are generally associated with appendicitis，并没有直接性的涉及关于test的使用正确性，我认为无关，起码要比BC弱

所以比较BC， 记得有人说过,false positive的情况总是要比false negative的情况好，所以选B

87338618

说得对

rainnight

我有仔细看了一下，觉得，关键还是在since前面那句话，文章的逻辑应该是说，以前是一有阑尾炎的迹象，不管三七二十一割了再说，后来发现其中２０%的人是unnecessarily的，后来有了一个仪器，可以比较精确的判断要不要割，但是仍然有２%的概率会误诊，但是结论说，用这种方法，能避免unnecessary的手术，同时也不会造成遗漏掉需要（necessary）手术的人，
而Ｂ说，那些２%被误诊的人，其实就是不需要手术的人，说明没有遗漏需要手术的人。。
说得很罗唆，不知道，对不对，各位路过得大大，都讨论一下撒。。

rainnight

厄，我还是不明白，为什么选Ｂ，楼上的能分析一下不？

gmatvictors

我觉得这道题的关键是句子的中心是disgnose而不是patient，所以很容易排除其他的选项。我选的时候也懵，感觉是B。谁知道就对了。