QUESTION TEXT: A positive correlation has been found between…
QUESTION TYPE: Weaken
CONCLUSION: Soot probably doesn’t cause the ailment.
REASONING: In cities with lots of soot, there are usually lots of other pollutants.
ANALYSIS: The argument said there’s merely a correlation between the ailment and the soot, and other pollutants are the cause. You’re supposed to weaken the argument by showing this correlation is actually significant. There are at least two weak points to the argument:
- The author only showed it’s possible the other pollutants are the cause. You can weaken the argument by showing they in fact aren’t the cause.
- The author only said that soot is usually accompanied by other pollutants. There may be cities with soot, but without other pollutants. What happens in those cites?
___________
- This strengthens the argument. The author wanted to show the other pollutants were the cause. This answer suggests they are, because the ailment occurs even where soot is absent but the other pollutants are present.
- This would help, if we knew that the ailment only occurs where soot is present. But the stimulus didn’t say that. The ailment is correlated with soot, but it’s possible it exists even without soot.
- CORRECT. This weakens the argument by showing that the ailment exists even when other pollutants aren’t there. So perhaps soot is the cause.
- This is complex, but it doesn’t mean anything relevant. I’ll explain its meaning with an example.
Example of situation: The pollutants smoog, snarf and blug are all correlated with a certain ailment. Therefore it’s possible that both snarf and blug each can cause the ailment. - This strengthens the argument. The author is trying to show that soot is not the cause. This supports that idea by showing that other pollutants may be the cause.
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Mary says
I am still confused about option D. Doesn’t that weaken the argument by making soot a potential cause for ailment along with the other air pollutant? The conclusion of the paragraph is that soot probably does not cause the ailment, but D shows that just because other air pollutant could cause the ailment does not mean soot is not an additional cause to the ailment.
ry says
For D, if there are many different pollutants available, and multiple pollutants cause the ailment, doesn’t that mean that soot itself could cause the ailment (because the argument argues that multiple present pollutants means that soot doesn’t cause the ailment?)
And for the correct answer, C, doesn’t this ignore the possibility that there could be some non-air pollutant that correlates with soot levels, but is the true cause of the ailment?
Thanks!
FounderGraeme Blake says
The problem with D is that there couple be 1,000 pollutants. In such a case merely having 2-3 pollutants as a cause doesn’t mean one of them is soot.
For C, the answer doesn’t need to prove the argument conclusively wrong. It merely has to “most weaken” the reasoning. C strongly suggests soot is the cause, because it shows the problem is constant where soot is constant, even if other pollutants vary.
Note: This is an old comment but I wanted to clarify the point.