Q20 - Polling data reveal that an

[f100875]

In my opinion, the flaw in the stimulus is that the group of people the polling choose is not representive enough for us to draw the conclusion, is this right?

[ManhattanPrepLSAT1]

Good thought, but I think they're looking for something else. The conclusion denies a cause and effect relationship. It would have been better had the argument in the stimulus not stated "connection" but rather "recognition of cigarette brand logos has no effect on smoking."

But the word "connection" does imply a bit more than correlation.

The flaw in the reasoning is that the argument fails to consider the possibility that effects of brand logo recognition may not be immediately apparent.

(A) commits the same flaw. It fails to consider that the effects of mercury exposure may take a while to appear. So, simply saying that effects are currently not present, does not imply there is no causal connection.
(B) does not commit the same flaw. This argument rests on the assumption that parents exert influence on their career choices of their children.
(C) does not deny a causal connection but rather posits that one influence is stronger than another.
(D) matches the stimulus structurally and would probably be the most tempting incorrect answer. But it denies a correlation rather than a cause and effect relationship. Also, this argument is valid, so could not match a flaw.
(E) does not deny causal connection, so cannot match the flaw.

Hope this helps! Let me know if you'd like me to expand anywhere...

[jaydizzle]

So, on these tougher questions particularly in the teens or 20s, if the structure matches and you are down to 2 answer choices it is a good idea to see if the answer choices actually have a flaw or sound logic?

I noticed that if I pick an incorrect answer it is because I picked something with an identical structure rather than flaw. This tends to happen when I look for another flaw or the flaw I want is actually not the answer.

[ManhattanPrepLSAT1]

Not only that, but almost always, when you're down to two on a Match the Flaw question, one of the two has similar structure but is actually a valid argument. If you can reason it out and spot the valid argument, you can eliminate that choice!

[mrudula_2005]

Not only that, but almost always, when you're down to two on a Match the Flaw question, one of the two has similar structure but is actually a valid argument. If you can reason it out and spot the valid argument, you can eliminate that choice!

Doesn't D have a flaw, though? It's essentially equating average life span with good health, no?

[ManhattanPrepLSAT1]

I stand corrected. That is a flaw committed in answer choice (D). The argument does assume a relationship between average life span and good health.

This answer choice is not flawed in the same way as the stimulus though. The reason is that answer choice (D) doesn't fail to consider that the affect would appear at some future point. Answer choice (D) controls for this by discussing average life span. The span of one's life would not allow for affects yet to be realized, since the life span is then over.

Good eye!

[theaether]

I could not for the life of me figure out the flaw in the stimulus. When this happens, I am pretty screwed when looking at the answer choices because usually 2-3 of them will definitely be flawed in their own ways. Does the LR book cover a list of flaws for parallel reasoning? I think I'm up to around chapter 9 or 10 right now, almost at the end of the book.

[ManhattanPrepLSAT1]

Actually, we advocate an approach that will help you avoid the need to memorize a list of flaws. We treat Flaw questions as Assumption questions and within the same framework as the rest of the question types within the Assumption family.

Try using this approach when attempting to describe the error of reasoning in an argument next time. Find the conclusion and the evidence for why it's true. In this case.

Less than 1% of 9 year-olds who can recognize cigarette brand logos currently smoke.
----- therefore --------
There is little or no connection between recognition of cigarette brand logos and smoking.

The argument takes for granted that because there are currently no effects that no effects will appear later on down the road.

Armed with the argument's assumption, you could convert that to abstract language "the argument commits a temporal flaw" more easily than if you tried to discern the flaw without first identifying the assumption.

Try that a few times on some Flaw questions and let me know what you think!

[jasonxu89]

I agree with previous discussion..

BUT I think both the stimulus and answer (D) commit the same flaw. The stimulus generalize from 9 year old children to the whole population and similarly, men are also not representative of the population (Women generally has longer life span than men so even there is a correlation between moderate exercise and good health, those men who exercise can have no longer average life span than men+women-men who exercise!)

The parrellel structure and reasoning was apparent to me and I chose D without any hesitation.

[ManhattanPrepLSAT1]

I completely agree that answer choice (D) is very tempting. For me, it's the most tempting of the incorrect answers, but the LSAT writer does insert a significant difference in answer choice (D) that's not there in the stimulus. The data reveal information about people at a particular point in time of their lives - 9 year olds.

Where answer choice (D) takes a wrong turn is when it says "throughout their lives." This is no longer taking evidence about a particular point in time and then extrapolating that no effects will ever occur. Since the evidence of evidence in answer choice (D) is not about a particular point in time, it doesn't match the flaw.

What do you think?

[irini101]

I think the flaw of stimulus lies in one scope shift: from nine-yr-old in the premise to the general population in the conclusion.

A is correct because it also contains one and only one scope shift: from 3-month in premise to long-term effect in conclusion.

D is flawed because it contains 2 scope shifts:
from men in the premise to the general popultion in the conclusion;
from average life span in the premise to good health in the conclusion.

Any thought would be appreciated!

[ManhattanPrepLSAT1]

I can see your point. I still think that the test-writer had something in mind about the difference between long-term and short term effects. Both the stimulus and answer choice (A) present the issue in such a way and address topics that frequently discussed as having long-term effects.

Answer choice (D) has the language "throughout their lives" that just leads me to suspect that the short-term vs long-term issue is probably what the test-writer had in mind.

Though I would feel comfortable eliminating answer choice (D) for the additional shift you mentioned regarding "good health" and "average life span."

Nice work!

[zainrizvi]

I dislike this question because it requires some external knowledge. I didn't realize there is a classic argument that maybe they won't smoke now, but in the future. You have to identify that they are making that assumption. But they are also making a billion other assumptions so I don't think it would be practical to just look at that right from the beginning.

Is there any way to get over this? I feel like if i ACTUALLY thought about the question I might have gotten that connection. But my strategy with parallel questions is usually the opposite - if I don't understand something, I generally just go strictly with the structure.

[ManhattanPrepLSAT1]

So it's about 50/50 on both Match the Reasoning and Match the Flaw questions when you'll go with structure and when you'll go with a described error of reasoning - such as circular reasoning or an ad hominem attack.

Try to stay more flexible with your strategy on these "parallel" questions. And reference what you know about correct answers on questions that ask you to describe the method by which the argument proceeds or the flaw in the argument. Your abstract descriptions here will be useful on Matching questions where structure plays less of a role.

Hope that helps!

[austindyoung]

Meh- so I chose (D). I now see the error of my ways.

Upon review, I noticed that (D) also has another element different from the stim.

In this stim- there is a group- 9 year olds. From part of that group a conclusion is made- namely, the ones who could identify the cigarette logos.

We are not told anything about the 9 year olds who could could not identify the cig. brands. Now, (A) does this as well. It draws from a group (dolphins)- and from a portion of that group (1,000 dolphins) a conclusion is drawn. It also contains the same error of the evidence feasibly leading to an opposite conclusion with the passage of time.

Now (D) does not do this. (D) is pretty tricky. One of the things it does is to divide up a group (men) between those who exercise moderately (which is a large percentage-- similar to the majority stated in the stim.) and those who do not exercise moderately.

But- it does not go on to make a conclusion about one part of that group- but instead makes a conclusion about the entire group. So- on top of the reasons listed- I think for this reason as well, it is incorrect.

Also- it contains the assumption- as pointed out, between life-span and good health. The stimulus makes an assumption as well, however it is more complicated and includes the "time shift error" (if you want to call it that, here) within it's assumption- as does (A). (D)'s seems more like a linkage error.

[amil91]

I originally crossed D out because I read it as not having a flaw, I didn't notice the language shift. But in the case of being stuck with A and D, IMO, keep it simple and look for the differences in the answer choices. D contains the term shift from life span to good health, whereas the stimulus and choice A do not contain any term shift.

[asafezrati]

I originally crossed D out because I read it as not having a flaw, I didn't notice the language shift. But in the case of being stuck with A and D, IMO, keep it simple and look for the differences in the answer choices. D contains the term shift from life span to good health, whereas the stimulus and choice A do not contain any term shift.

Actually the stimulus goes from information about 9 year olds to a general conclusion (not restricted to 9 year olds).
Answer choice D goes from information about the male population to what is true in general.
How come this isn't a match? Is it because there is an additional shift in D?
A certainly doesn't have such a shift.

Also, "connection" is not limited to causation. While the stimulus rules out both causation and correlation, and perhaps even an indirect connection through a third factor which affects both phenomena, A rules out only the causation relationship in which Merc is the cause and change in dolphin health is the effect.

This question isn't one of their best.

[Mab6q]

D simply contains more variables in the premise than we need , and it makes a relative claim, concerning those men that exercise and does that don't, whereas the stimulus and A make a general claim about the group under consideration as a whole.

[JeremyK460]

Now (D) does not do this. (D) is pretty tricky. One of the things it does is to divide up a group (men) between those who exercise moderately (which is a large percentage-- similar to the majority stated in the stim.) and those who do not exercise moderately.

just an fyi

a large percentage doesn't necessarily mean 'most' or 'majority'

'a large percentage' is too ambiguous given the context
in this context, it seems logically equivalent to say 'many people who'