Q23 - Many scientific discoveries have suggested

[dan]

23. (C)
Question type: Strengthen
The author of the argument concludes that there isn’t enough information to prove that a certain input (melatonin) has the same impact on a specific subgroup (those with insomnia) as it does on the general population, because there isn’t enough evidence directly related to that subgroup. Answer choice (C) addresses this issue, and shows that, for those with insomnia, melatonin may indeed have a different impact than it has for those in the general public.

(A) is an attractive answer, because it seems to hint that insomniacs drove down the average correlation in certain studies. However, other factors, such as location, could have impacted the differences between studies. Also, remember that correlation doesn't mean causation - so X and Y might have a weak correlation, but X may be a factor in causing Y regardless. Similarly, two things can always occur together (high correlation) but neither one could cause the other.
(B) is also an attractive answer, but it’s not necessary for one particular study to be representative of the entire population _ it could be that the studies, collectively, accurately represent the entire population.
(D) does not address the specific conclusion.
(E) is too extreme and goes well beyond the degree of the author’s opinion.

[goriano]

so X and Y might have a weak correlation, but X may be a factor in causing Y regardless.

Could you explain this in more detail? How is it possible if X and Y are not correlated that X might still cause Y?

[bbirdwell]

Well, that's not exactly what Dan said, and the differences are important. X and Y can have a WEAK correlation, and X can be A FACTOR in causing Y.

This is much different than "not correlated" and "cause."

(A) is a really appealing choice because of the way it's worded. I think what Dan was saying is this: the conclusion is "melatonin is not NECESSARILY helpful for insomnia." (A) says "one study of melatonin and sleep-inducement had a weaker correlation than another."

This isn't enough to strengthen the argument's logic, however, because there are too many questions left un-answered. Anytime we are dealing with subgroups, it's important that the information support the correct subgroup. It could be true that every single insomniac in the study was affected, even though the group as a whole had a weaker correlation, in which case the argument would actually be weakened.

© points at what I just mentioned. If EVERY person affected was NOT an insomniac, then the argument is strengthened -- melatonin doesn't seem to helpful for insomniacs.

I suggest that when you're practicing and you're in a bind between two choices in a sampling/study argument, err on the side of guessing the choice that applies to the correct subgroup. See what you learn through that kind of trial and error.

[the_sork]

I would suggest that A is incorrect because the fact that there was a weaker correlation does not mean that the correlation was weak. It could be that melatonin actually did induce sleep among people who suffered from insomnia but that it was less effective. This would not strengthen the author's thesis that melatonin does not help induce sleep for people with insomnia. This answer choice should therefore be eliminated.

[nflamel69]

this question is upsetting me. I was between A and C, and I feel like I can find faults in both of them. Like someone above suggested, a weaker correlation does not indicate weak correlation, sure, i'll take that. But in C, it says only people without insomnia are not significantly affected by it. So what if they are not significantly affected by it, what if they are affected by it moderately? how would this strengthen the conclusion it doesn't help to treat insomnia

[acechaowang]

A is wrong because although there might be a weaker correlation, the melatonin tablet could still help treating insomnia. C direct got into the issue saying that it is not helpful at all. so C is right.

[xingdavid]

A is wrong because although there might be a weaker correlation, the melatonin tablet could still help treating insomnia. C direct got into the issue saying that it is not helpful at all. so C is right.

I don't think that this addresses the point brought up by nflamel69. C doesn't say that melatonin isn't helpful at all for people with insomnia, it says that only subjects without insomnia were significantly affected by the dosage. So it leaves room for the possibility that melatonin could have had at least a minor effect in helping with insomnia.

The conclusion seems to be:

"Just because melatonin tablets can induce sleep doesn't mean that they can help treat insomnia."

Are we to assume that in order for melatonin tablets to treat insomnia, they would have to have a significant effect on subjects with insomnia?

[rshapiro14]

This question is a classical example of: These people said A but they are wrong. Why? Because of reason(s) B. But the problem with the argument is that the evidence (reason B) really doesn't show that A is wrong.

Here is the argument: These studies say that melatonin can induce sleep, but these studies do not apply to insomniacs. Why? Because these studies have two issues: most didn't include insomniacs, and because only a few people were significantly affected by melatonin. But there is a HUGE assumption here. What if in those studies the people who were significantly affected by melatonin where insomniacs??? Well then certainly the conclusion about these studies is wrong, they would apply to insomniacs. The correct answer needs to strengthen the conclusion by closing this gap.

Answer choice (C) does this. It says that the people significantly affected by melatonin were not the insomniacs.

Answer Choice (A) doesn't address the gap in this argument. Even if there was a weaker correlation in the studies with the insomiacs then without there still is the evidence that SOME PEOPLE were SIGNIFICANTLY affected by melatonin and those people still COULD BE insomniacs even if, overall, the correlation is weaker. This doesn't strengthen the argument that the studies do not apply to insomniacs. They still could.

The importance here lies in correctly identifying the conclusion. Does it say that melatonin isn't helpful for insomniacs? No. It says that the studies done do not show that melatonin is helpful for insomiancs. But with the evidence given in support of the conclusion, it's possible the studies DO show melatonin helps insomnicas. This is a gap that needs to be filled.

Does the answer 100% prove the conclusion, no, but it is the only one that strengthens the conclusion.

[yooj]

(C) says only the subjects without insomnia were significantly affected by doses of melatonin.

And the conclusion of the Stimulus is "But this does not mean that melatonin is helpful in treating insomnia."

Nowhere in the stimulus appears an indication that "in order to say A is helpful in treating insomnia, A must have a significant effect."
Even if A did not have "significant" effect, it could still induce some sleep. And "helpful" in treating does not necessarily mean that it should eliminate the original source of insomnia completely, or that it should get the sleep cycle back to normal. I think if it induces some sleep, it is safe to not exclude "not having significant effect" from being "helpful in treating."

And, by this, I am not trying to attack the argument (we have to accept it as true), but just trying to say there is a hole in the argument, and given the two choices (between (A) and (C)), (C) supports in a way that is committing the same error/assumption that "helpful" means necessarily having a signifiacnt effect.

Guess this does not leave any option to be very inticing, but if something has to be chosen, wouldn't (A), in this sense, a "safer" answer choice and thereby most strengthens the argument?

Thanks in advance!

[samuelfbaron]

Yup, I have to agree with the above poster.

I solved this one by paying specific attention to the "those significantly affected" clause.

Basically, if those who were significantly affected were not insomniacs then the conclusion that melatonin is not helpful in treating insomnia is warranted - based on the premises we are given.

[ManhattanPrepLSAT1]

Lets take a look at this one...

The argument concludes that although some studies have suggested that taking melatonin tablets can induce sleep, this does not meant that melatonin is helpful in treating insomnia. Why? Well two reasons are given. First, most of these studies did not include people with insomnia. And second, only a few of the subjects given melatonin appeared to be significantly affected by it.

We're asked to strengthen the argument (note; that does not mean prove the argument). All we need is an answer choice that makes the conclusion more likely to be true. And remember the conclusion is not that melatonin is not helpful, but that there is not evidence that it is helpful.

Answer choice (C) strengthens the argument by adding that only subjects without insomnia were significantly affected by melatonin. That means those with insomnia were not significantly affected. This eliminates one way in which there could have been support for the claim that melatonin could be helpful in treating insomnia.

Incorrect Answers
(A) fails to specify whether it was the insomniacs or noninsomniacs for which the weaker correlation was found. Maybe the insomniacs actually did experience induced sleep, while the noninsomniacs did not.
(B) fails to address insomniacs. This questions the representativeness of the studies, but does not strengthen the conclusion because the conclusion is whether the fact that melatonin can induce sleep means that melatonin can be helpful in treating insomnia.
(D) is both too weak and fails to tell us something about insomniacs. We'd really like to know how insomniacs react to melatonin.
(E) fails to strengthen the argument because we cannot say whether some insomniacs who took doses of melatonin were not significantly affected by it.

[wgutx08]

I'm not sure I follow you, Matt --- I thought if "many scientific studies" have shown correlation between melatonin intake and sleep inducement in ppl without insomnia, it would be very reasonable and safe to assume that the weaker correlation in (A) was due to the non-insomniacs part??

Comparing the two tempting choices A and C, I feel C is actually just one step more specific in description than A. So in C, it's not just that the correlation in the insominiacs part is weaker than in the non-insomniacs part (as stated in A), but more specifically, the correlation in the insominiacs part is zero (insignificant).

So A would allow some help in sleep by melatonin for the insomiacs, though we are not sure if this help is large enough for melatonin to be used in "treating" insomnia (I imagine any treatment has to have a minimal amount of positive effect to be justified against potential side effects). Whereas in C, melatonin would not help insomniacs at all.

I think A is a strengthener, but C is much stronger and is certainly the choice that "most strengthens".

[jmlopiano]

After reading mattsherman's response, and after rereading the answer choice for probably the eleventh time, I understand where the issue with (A) pushes into the realm of a non-strengthen. (A) states: "A weaker correlation between taking melatonin and the inducement of sleep was found in the studies that INCLUDED people with insomnia than the studies that did not." In other words, as mattsherman already stated, we do not know if it was actually the insomniacs within the group that [i]included[i] the insomniacs that were responsible for the weaker correlation.

[roflcoptersoisoi]

Premise: Most of the studies that suggest that taking melatonin tablets can induce sleep examined only people without insomnia.
Premise 2: In some of the studies only a few of the subjects given melatonin appeared to be significantly affected by it.
Conclusion: Melatonin not necessarily helpful in treating insomnia.

Assumption: In the studies that did include people with insomnia, the latter was not affected by the melatonin tablets

(A) Tempting, but it does not strengthen the conclusion. Remember you can't always use a relative claim to justify a absolute one, so in this context, weaker does not mean weak. It follows that just because there may have been a weaker correlation between taking melatonin and inducing sleep among insomniacs, perhaps they still significantly affected by taking the melatonin tablets.
(B) This just attacks the studies, has no bearing on the reasoning structure.
(C) This matches nicely with the gap we identified, keep for now.
(D) This has no bearing on the argument. This mentions neither the melatonin tablets nor if the people in the control group were insomniacs.
(E) We have no idea whether insomniacs in the studies studies were significantly by it.