一道有意思的逻辑题目，大家来试试

ansionjoe

Nearly all adults in the community of amaretti, including pregnant women, engage in ritual fasting throughout Dec AND Jan. A recently completed study has revealed that, on the annual cognitive tests given to Amarelti's first-graders in each of last ten years, nearly 25% of the students scoring in the top fifth of the class, but only about 2% of those scoring in the bottom fifth, were born in November. Because pregnancy lasts nine months, only the mothers of children born in November would not have fasted during the entire pregancies; therefore the ritual fasting must have detrimental effects on developing babies.

which of the following ,if true, most weakens the argument?

A No comparable data are available for students who were in first grade in Amaretti more than 10 years ago

B First-grade students who are absent from school when the cognitive tests are administered do not have the opportunity to take them at a latter time

C Each school grade in Amaretti is composed of students born between NOV 1 of a certain year and Oct 31 of the following year

D In Amaretti, non-cognitive birth defects, such as physical deformities , occur at a much lower rate among babies in Nov than among babies born in other months

E In typical year in Amaretti, between one-fourth and one-fifth of all babies are born in NOV.

暂时不写答案，请写出你的分析和答案~~

来试试吧

Jagabee

I chose E but it was incorrect. E may be able to explain the 25% in the top quintile, but it doesn’t explain the 2% in the bottom quintile. If this were true, then the %’s in both quintile would be higher.

OA is indeed C. It means that the November kids are the oldest kids in the class and thus have more development time compared to other kids in the class.

alzn2765

我觉得答案是C

果因推理找削弱

前提（果）：on the annual cognitive tests given to Amarelti's first-graders in each of last ten years, nearly 25% of the students scoring in the top fifth of the class, but only about 2% of those scoring in the bottom fifth, were born in November. Because pregnancy lasts nine months, only the mothers of children born in November would not have fasted during the entire pregancies
结论（因）： the ritual fasting must have detrimental effects on developing babies

C说Each school grade in Amaretti is composed of students born between NOV 1 of a certain year and Oct 31 of the following year
这些娃是当年2月到下一年3月出生的，只有当年9月和10月出生的娃其母在怀孕期间经历了禁食，在剩下的12个月出生的娃其母都没有经历过禁食，无法解释为什么只有11月出生的娃cognitive tests成绩特别好（同样条件不同结果）。一定是有其他原因导致了这种差异化的表现，而这个原因才是11月出生的娃cognitive tests成绩优异的root cause。

逻辑角度解释：

果--->因

逆否等价：

非因--->非果

如果
因---->非果 为真
则证明“因” "果"关系不存在，一定有其他“因”导致“果”
C中在剩下的12个月出生的娃其母都没有经历过禁食，也就是有“没有禁食”这个共“因”，但cognitive tests的成绩差距很大，也就是“非果”。C就是因---->非果的削弱。