一題傷腦筋的邏輯

loyse66328 · 发表于 2003-5-29 12:06:00

Blood banks will shortly start to screen all donors for NANB hepatitis. Although the new screening tests are estimated to disqualify up to 5 % of all prospective blood donors, they will still miss tow-thirds of donors carrying NANB hepatitis. Therefore, about 10 % of actual donors will supply NANB-contaminated blood.
A. Donors carrying NANB hepatitis do not, in a large percentage of cased, 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.
E. The donors who will still supply NANB-contaminated blood will donate blood at the average frequency for all donors.

答案是A.
基本上，题目我看不太懂，更不用说里面的因果逻辑了，有高人可以把题目翻成中文吗，tks.

jingshuijing · 发表于 2003-5-29 14:01:00

血库不久将开始检验所有的献血者，因为（NANA hepatitis）NANB肝炎。尽管新的检测被估计会使所有捐血者中5%以上的人不合格，他们仍会漏掉2/3的带有NANB肝炎的捐血者。因此，真正捐血者中大约10%的人将提供含NANB的血。
A带有NANB肝炎的捐血者不会带有其他的（通过可依赖的按常规进行的检测可以检测出来）的传染病
B带有NANB的捐血者不会自己发展此疾病
C被估计的数目是低估
D在潜在捐血者中发现NANB的可能性比在普通人群发现的可能性小
E带有NANB的捐血者将以所有捐血者平均捐血的频率捐血
解释：5%占1/3，即总共带有NANB的是15%，排除5%，漏掉的就是10%
此数字演算基于一个前提，即带有NANB的人不会因为带有其他疾病而被检测出来，
如果真的因此被检测出来，那漏掉的带有NANB的捐血者就不是10%了，只能少于10%

loyse66328 · 发表于 2003-5-29 17:41:00

原来如此，我完全会错意了，真的很感谢你的翻译及解释，要不然我永远都搞不懂了, tks!

一題傷腦筋的邏輯

一題傷腦筋的邏輯

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