Q12 - A recent study found that snoring,

[paulinoinny]

Ahh...didn't think the stimulus was confusing, but I would like to know why (C) is not the answer. Is it because it starts with "most"? I guess if something else was the cause of both snoring and smoking then that would ruin the argument. But would still like some clarification.

[christine.defenbaugh]

Thanks for posting, paulinoinny!

Let's break this weaken question down from the top.

PREMISES
Snoring not common among smokers or non-smokers
Snoring more common among smokers.
CONCLUSION
Smoking by itself can induce snoring.

This is a classic causation/correlation mistake. We know A is correlated with B, and the author assumes A therefore must cause B. Classic rebuttals to this are:

1) reverse causation: B might cause A
2) third party: C might cause both A and B
3) coincidence!

(A) nails the target by introducing a third party, stress, that could be responsible for causing both snoring and smoking, which would handily explain the correlation.

Not the Problem
(B) This doesn't explain the connection to snoring.
(C) The conclusion was only that smoking could induce snoring, not that it was the only possible way to induce snoring. If most snorers don't smoke, then their snoring is caused by something other than smoking, but that's okay - it doesn't damage the conclusion.
(D) We were already told this in the premise!
(E) Who cares what smoking and snoring cause, we want to know what causes THEM!

Does that help clear things up a bit?

[WaltGrace1983]

So for (C), what you are saying is this: the conclusion gives us the causal claim that smoking can induce snoring. If we interpret the arrow very softly, we might say something like smoking → snoring. However, (C) basically tells us (again, interpreting the arrow very softly) that ~(snoring → ~smoking). So in other words, we could probably infer that some snorers smoke and some do not.

However, what we really want to know is what causes the snoring in those snorers that smoke! Is it the smoking that causes the snoring? This would strengthen the claim. Is it the snoring that causes the smoking? This would weaken the claim. Because we don't have any causal language in (C), it really cannot be right. We need to know about causation! Giving us more correlation is not going to do it!

Is that about right?

As for (A), it is correct because it addresses the causal claim. It says, "mmmm NOPE! ~(A → B). Instead, C → A & B.

This reminds me a lot of answer choice (C) in 37.4.11, the squirrel and sugar one. Even if we say that some trees are less frequently tapped, this doesn't address the causal claim. We want to know WHY trees are less frequently tapped.

[christine.defenbaugh]

Interesting thoughts, WaltGrace1983!

I must admit, I tend to get a little turned around with arrows used for causal things - my brain interprets the arrows as conditional arrows, and that's obviously incredibly dangerous. I realize that you suggested "interpreting the arrow very softly", but I worry a bit that even with that caveat that this approach is attempting to be a little too mathematical.

The thing about (C) is really that that it simply does not matter what percentage of the snorers smoke. It doesn't affect the correlation *either way*, no matter what percentage we set it at. We already know, from the stimulus, that there are some smokers who snore, some smokers who don't snore, some non-smokers who snore, and some non-smokers who don't snore. So, any interpretation of (C) that nets you one of these facts is work that we didn't need to do!

Now, let's talk about the nature of the correlation in the stimulus: snoring is MORE COMMON among smokers than non-smokers. What does that mean? It means that whatever the 'snore-rate' is among non-smokers, that 'snore-rate' is a little higher among the smokers. Obviously smoking can't be the cause of all snoring, since we know there are at least some snorers who don't smoke.

So, we're not attempting to explain ALL SNORING, or even "all snoring within the smoker group". We're just trying to explain the difference in rate. All we really want to do is explain why we have a few extra snorers in the smoker group.

Even if 95% of the snorers don't smoke, that doesn't change the fact that the snore-rate is still higher among the smokers. Not only does it fail to weaken the potential causal connection, it doesn't strengthen or damage any correlative connection there either.

Does that make sense?

[yihanqin]

Hi, I do see that A attack the gap, but then I see "certain individuals" and the word "certain" makes me hesitate. Does it matter here?

[keane.xavier]

I certainly struggled to eliminate (C). However, I eliminated it in a different way than what was posted here by Christine. I'd love to hear whether this is a correct way to proceed or not or any general feedback that you may have. Anyways, here is how I went about eliminating (C):

C. From “most snorers do not smoke” we may infer that if you smoke, you’re most likely not a snorer. But we know this already: we know that snoring is uncommon in either the smoker or the nonsmoker groups. Furthermore, the statement “most snorers are nonsmokers” doesn’t tell us anything about the amount of nonsmokers that snore. There could be more smokers that snore or more nonsmokers that snore. But we know from the stimulus that it isn’t common for nonsmokers to snore, and we know that a study found that more smokers snore than nonsmokers snore. So this answer choice, like answer choice (D), doesn’t present any new information that contradicts the information that we’ve received in the stimulus. If the answer choice doesn't present new information, then it cannot by itself weaken the argument.

[SunnyS929]

I found this one very tricky.

As for AC A, I think I understand that AC A meets the target by introducing a third party, stress, that could be responsible for causing both snoring and smoking. However, I am wondering that what if stress indeed causes both snoring and smoking, and at the same time, smoking causes snoring. A third party cannot exclude the possibility that smoking doesn't cause snoring.

As for AC D, I understand that it indeed doesn't infer any hard causation. But I think it is a quite soft one. The more cases are, the better chance that smoking causes snoring. I think in scientific research, it is indeed has such inference?

Could someone help me with this confusion? Thank you!

[JimW371]

(C) is wrong because the premise simply told us that snoring has a higher percentage in smokers than non-smokers. Non-smokers could outnumber smokers which makes "most snorers do not smoke," but the higher percentage in smokers could still be caused by smoking.

(D) is wrong because this is a premise booster. We already know that snoring is not common in either group.

A percent and amount flaw.