Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.
大全-2-19. The argument above depends on which of the following assumptions? E/A
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.（A）
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.
答案是A, 我选了E. 不是很明白, 请教. 谢谢.
Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.
大全-2-19. The argument above depends on which of the following assumptions? E/A
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.（A）
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.
答案是A, 我选了E. 不是很明白, 请教. 谢谢.
原文说的5%对应1/3的donors carrying NANB hepatitis,所以文章说10%对应2/3的donors carrying NANB hepatitis.
可是要是A不成立的话,那文章说的10%是不一定对应2/3的donors carrying NANB hepatitis.也就是它的推论不成立.
原文说的5%对应1/3的donors carrying NANB hepatitis,所以文章说10%对应2/3的donors carrying NANB hepatitis.
可是要是A不成立的话,那文章说的10%是不一定对应2/3的donors carrying NANB hepatitis.也就是它的推论不成立.
麻烦竹子翻译一下原文吧，没看明白
从哪里看出：原文说的5%对应1/3的donors carrying NANB hepatitis,所以文章说10%对应2/3的donors carrying NANB hepatitis.
麻烦竹子翻译一下原文吧，没看明白
从哪里看出：原文说的5%对应1/3的donors carrying NANB hepatitis,所以文章说10%对应2/3的donors carrying NANB hepatitis.
Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis.
Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.
大全-2-19. The argument above depends on which of the following assumptions?
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
谢谢先，但是还是不明白...
两个范围的问题是么?
5%的人会被过滤掉，这5%对应的是1/3的病人被过滤掉...
看来我得放弃了 实在是想不明白 看了40分钟了
先谢谢斑竹帮忙解答和晴天小狗参与讨论。一直保持沉默，因为想了好几次没有想通。今天好象突然有了思路，是不是这么理解：
题目给出的论点是说新的技术只能发现1/3有这种毛病的人，那么这个论点的依据应当是，剩下的人由于其病症的特征是没法通过这种新技术或者是已有的任何老的技术能发现的，所以结论是有2/3的这种毛病的人是不能被发现的。因而答案A是对的。
不知道这样的思路和理解对不对？谢谢。
Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis
5%对应1/3的donors carrying NANB hepatitis
好晕
I think we can forget about the 5% or 1/3 in the first place. My view is that the key point is that some of the NANB-contaminated blood cannot be identified during the testing. Then what is the assumption that such NANB-contaminated blood cannot be identified? - the answer should be that current testing method or the existing methods cannot identify them. Or we can think in this way, what if the current testing method or the existing methods can locate them by whatever characteristics? then no NANB-contaminated blood will be omitted in the testing.
I agree this is very much confusing and I hope I could express myself more clearly. What do you say about this thinking process.
再来一记，看看是不是少晕点：
我觉得先不去想1/3啊，5%的问题。我们这么来想：题目说有个新的方法能够找出部分的这种病症的献血者，然后说但是还是会漏掉另外剩下的那些病症者。最后问我们这样的推理过程的依据是啥。
A说，这些患者并在较大共性的层面上存在一个症状(or whatever)是现有的检测方法去测试的 -- 即，如果存在这么一种共性的症状并且是被测试的指标之一，那么这些病人就不会在测试中被漏掉了，那么上面的推理结果就不会出现了。所以题目中的表述成立的依据就是A成立。
你觉得呢？
我只能先谢谢您的解释，过两天再看吧
有时候就是这样 脑子突然就迷了，越看越迷...
文章的思路很清楚
5％的disqulify还不够，会漏掉2/3，即5％就是没有漏掉的1/3。因此文章说的是将有10％的人继续作为捐献者。这个推理似乎无懈可击。
但是如果有人在做screen检测的时候同时有文章所提及的NANB病和文章未提及的病，如果是因为，文章未提及的病而被判定为不合格，那么真正携带NANB病的人将多余10％
或者说A排除了别的情况，加强了结论的正确性，保证了只有一个变量
谢谢竹子，
5％的disqulify还不够，会漏掉2/3，即5％就是没有漏掉的1/3。因此文章说的是将有10％的人继续作为捐献者
这句话 我再慢慢理解吧
其实选项上倒是没有问题，我就是对原文说的，感觉有点怪
滤掉了5%，但是有2/3没被滤掉，于是就胜10%
这里面有个假设，就是那5%都是这个病的，如果不是呢，结论就不成立了
Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 percent of all prospective blood donors, they will still miss two-thirds of donors carrying NANB hepatitis. Therefore, about 10 percent of actual donors will still supply NANB-contaminated blood.
翻译一下:
血银行即将开始检查所有的捐血者来排除甲乙肝炎。 尽管这个新检查方法会使得5％的捐血者不符合条件， 仍然会有2/3的携甲乙肝病毒的捐血者不能被排除。 因此， 大概有10％的捐血者会提供感染甲乙肝病毒的血。
问assumption：
5% = 1/3
10% = 2/3
A 选项说带甲乙肝的病人不会大面积的携带其他可被有效检查的病毒。
如果A选项不成立。 那么 2/3中会有很多人因为携带其他病毒而被排除。 所以就会小于10%.
E 是无关项。 因为一直在比较人数， 不涉及到捐血频率和捐血量。
大全-2-19. The argument above depends on which of the following assumptions? E/A
(A) Donors carrying NANB hepatitis do not, in a large percentage of cases, carry other infections for which reliable screening tests are routinely performed.
(B) Donors carrying NANB hepatitis do not, in a large percentage of cases, develop the disease themselves at any point.
(C) The estimate of the number of donors who would be disqualified by tests for NANB hepatitis is an underestimate.
(D) The incidence of NANB hepatitis is lower among the potential blood donors than it is in the population at large.（A）
(E) The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.
文章的思路很清楚
5％的disqulify还不够，会漏掉2/3，即5％就是没有漏掉的1/3。因此文章说的是将有10％的人继续作为捐献者。这个推理似乎无懈可击。
但是如果有人在做screen检测的时候同时有文章所提及的NANB病和文章未提及的病，如果是因为，文章未提及的病而被判定为不合格，那么真正携带NANB病的人将多余10％
或者说A排除了别的情况，加强了结论的正确性，保证了只有一个变量
偶现在十分明白鸟。。。
不过那个“多余”偶觉得应该是“少于”才对。。。
终于想通E为啥错了：献血频率与丙肝的检出率无关，不管献血次数如何变化，该人群被查出的概率不变，总是1/3
痛苦啊痛苦
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