Q23 - Several carefully conducted studies

[greatwhiteshark100]

Hi, is the flaw here not pointing out the normal percentage of heart disease that would occur under meat eating and comparing that to vegetarian or what?

Thanks

[ManhattanPrepLSAT1]

That's exactly right. The argument assumes that 75% is a high figure. What happens if 85% of nonvegetarians reach the age of 50 without a heart attack? We couldn't say that eating a vegetarian diet would reduce your chance of a heart attack.

Good work in spotting the flaw! That said, as is true for most match the reasoning/flaw questions, the real work on this one is in the answer choices. Let me know if you need any help working through some of them.

[skapur777]

I thought the flaw was that they give a statistic but they never give us the obvious opposing numbers that we'd want to see.

For example,

A certain percentage of vegetarians reached a certain age without developing serious heart disease.

Curiously, they leave out the percentage of nonveggies that reached the same age without serious heart disease.

And that is what led me to E, which shows that people who exercise regularly are able to handle stress but leaves out people who exercise infrequently and their ability to handle stress.

A- tempting for me, but the line that starts with "to avoid harm..." is all wrong for me and I eliminated
B- compares two different groups, don't really see much of a flaw here. eliminate
C- no...way off
D- compares two groups again, eliminate for reasons similar to B
E-nails it.

Did I just get lucky? I'd love to see your reasoning through the answer choices with your own description of the flaw.

[ManhattanPrepLSAT1]

Nope, you have it right. You and I said the same thing, we just said it in different ways.

Take a close look..

A certain percentage of vegetarians reached a certain age without developing serious heart disease.

Curiously, they leave out the percentage of nonveggies that reached the same age without serious heart disease.

The argument assumes that 75% is a high figure. What happens if 85% of nonvegetarians reach the age of 50 without a heart attack? We couldn't say that eating a vegetarian diet would reduce your chance of a heart attack.

We're both pointing to a possibility that the argument failed to consider - that the percentage of people who reach 50 without a heart attack could be higher for nonvegetarians than for vegetarians.

Great job! Always be on the lookout to expand your repertoire of describing the same assumption or flaw.

[lhermary]

Can someone go into more detail as why E is preferred over C?

[tamwaiman]

Can someone go into more detail as why E is preferred over C?

Stimulus: We can conclude from this (75% vegetarians reached age 50 without serious heart disease)

(C): Since smoking increases one's chance of incurring heart disease.

(E) This (exercising regularly handles stress) shows something.

Like stimulus, (E) concludes from a phenomenon, but (C) clearly indicates a causal relationship.

[ManhattanPrepLSAT1]

Another way to look at this - though tamwaiman has great points - is that answer choice (C) offers a recommendation that doesn't allow for personal choice. Why should the government make coffee less accessible? Only if you'd want to prevent dental problems later. Answer choice (C) should should have said that, "so people who want to avoid the risk of dental problems later should avoid coffee."

Hope that helps!

[timmydoeslsat]

I just did this problem in the LR book. I was surprised to not see the correlation issue in this one. It was the thing I noticed first. It turned out to not play a big role in determining the correct answer.

I now see the issue of not knowing the other group, the non vegetarians, and their health in relation to the vegetarian group.

However, isn't the correlation to causation issue a glaring one in this respect? While it is true that we do not know about the second group, we also are not sure what the cause is of these vegetarians living to this age, yet the argument attributes the lack of meat.

The conclusion of a third party being involved helped to eliminate C and D.

I eliminated B for the reason that it states in a premise that cigarette smoking increasing one's chances of incurring heart disease.

A is not even close.

[anjelica.grace]

I, too, initially picked up on the correlation issue, but after reading the explanation, I feel that the correlation issue is somewhat related to the control group issue.

In most stimuli that concludes causation, the author cites evidence of correlation, as is the case here. However, because this stimulus specifically refers to a group in a study, the control group (or lack thereof) is a more specific issue because of the nature of the evidence.

Basically, correlation is often the flaw related to causation, but because this stimulus (and the corresponding credited response) involves a group with a particular trait (the proposed cause), you can pinpoint the flaw one step further and cite the lack of a control group. Otherwise, if you are just talking about say, unemployment causes depression, depending on the evidence you use, the control group may not be an issue and you can fall back on the broad correlation issue.

Hope that makes sense!

[austindyoung]

Well- I saw this a little differently. If a Geek sees some error in my ways, please let me know. I do not want to develop bad habits.

I'll admit, that I didn't think about, "Well what about those who DON'T eat meat?" I just that the glaring problem was the statistic, and then the strong language, "We can conclude..."

So here is how I saw it (by the way, I am not saying that the other explanations are wrong- I'm pretty much posting this to make sure I'm not doing something wrong):

(Note: I'm really truncating the language here)

Premise (Stat): Studies show 75% veg eaters---> 50 avoid heart prblm

Premise(Intermediate Conclusion):THEREFORE: veg eater---> (causal) avoid heart prblm

Conclusion: THEREFORE: avoid heart prblm---> veg eater

So, I saw the problem as having a Mistaken Reversal for the conclusion and the huge scope shift from, "a study" to "We can conclude."

I looked for this in the answer choices.

A) Awkward argument that does not parallel our stim. This adds a new element into the conclusion, unlike our stim.

B) This one was tricky for me personally. But, the second premise is not an Intermediate Conclusion, like the stimulus was. Also, the Conclusion is in the Contrapositive. This argument is valid.

C) This is talking about a correlation. Our stimulus is about causation. As mentioned, it introduces a new variable in the Conclusion.

D) Not invalid. ~Exercise---> shorter life expec.
2nd part of that sentence: Exercise--->~shorter life expec. So the conclusion seems to just be a contrapositive of the first conditional. Valid.

E) Same pattern of: Premise (most in place of 75%)---Intermediate Conclusion (This shows...)--- Conclusion (Mistaken Reversal)

Maybe I did this wrong, or in not the best way. I dunno... let me know whatcha think!

[tangdanni422]

I would like to say something about the answer choice C, and please correct me if I am wrong...

The stimulus assumes that avoiding eating meat has a causal relationship with avoiding serious heart disease. But the answer choice C does not necessarily do so. C just says there is a correlation rather than a causation, and based on this correlation suggests that the government should do something. This might be flawed, since it might be unreasonable to reach a normative conclusion merely because there is just a correlation, but I am hesitate to think C assumes a causal relationship simply from it recommends a course of action. Maybe something else causes both the regular coffee drinking and the dental problems, but people can be prudent to recommend a course of action before they can pinpoint the real factor. Am I right? Should I assume the passage implies a causal relationship here?

Furthermore, if C just bases its conclusion on a simple correlation, it does not need to have the fact of the other group that is required in the stimulus to compare to reach a conclusion of a causal relationship.

Because C does not rely on an assumption of causal relationship, the answer choice is different from the stimulus and therefore wrong.

[maryadkins]

This is one of those classic bad arguments that you see all over the news regarding scientific "findings" and how you should use them to make health decisions.

We have a couple of problems here.

1. Just because a low rate of heart disease is correlated with vegetarianism doesn't mean vegetarianism is causing the low rate.

2. Maybe 75 percent is actually not that good. The conclusion says to "reduce" their risk what people should do, but we don't actually know what it's being compared to. As Matt mentioned, what if the rate of heart disease among non-vegetarians is even lower?

(E) has the same two flaws: both the correlation being taken as causation, and the second flaw"”we don't know how many people who don't exercise can handle stress. Maybe it's all of them! That's more than "most"!

(C) doesn't infer causation. I agree with you, tangdanni422. Well put.

Easy ways of getting rid of the others:

(A) has too many pieces; it's all over the place.
(B) could be tempting, but it's actually a stronger argument than our stimulus. Studies have shown that not smoking is better than smoking. We ARE told what the comparison is is here, so it isn't assumed.
(D) is the same as (B).

Hope this helps!

[WaltGrace1983]

I'll add my two cents to this one. I saw it (only slightly) differently - or perhaps I am just combining all of your responses. There are three pieces of the argument here:

(P) Studies show 75% of vegetarians reached age 50 w/o heart disease
(IC) Avoiding meat increases chances of avoiding heart disease
(C) People who want to reduce risk of heart disease shouldn't eat meat.

Correlation/Causation: just because 75% of vegetarians didn't have heart disease, does that mean that avoiding meat has anything to do with it? Maybe these 75% of vegetarians rigorously exercises everyday and drank red wine. This is what I am looking for. In addition, I also want some kind of recommendation in there.

(A) Discussion of a correlation (driving over speed limit) without discussion of causation ("driving over speed limit causes something"). Eliminate.

(B) Discussion of a correlation, check. Recommendation, check. However, the part that got me was "since cigarette smoking increases one's chances of incurring heart disease." This is not so much a conclusion about causation as it is just a given fact. This looks dicey.

(C) Missing assertion of causation. Eliminate.

(D) Missing assertion of causation. Eliminate.

(E) Correlation (exercise: stress), check. Discussion of causation (Exercising regularly → Decreases chances of stress), check. Recommendation, check.

This looks a bit better than (B) because it has more of an intermediate conclusion rather ("this shows that...") than another premise ("Since cigarette smoking...").

Otherwise, I think (B) and (E) are very similar.

How does that look?

[maryadkins]

I'll add my two cents to this one. I saw it (only slightly) differently - or perhaps I am just combining all of your responses. There are three pieces of the argument here:

(P) Studies show 75% of vegetarians reached age 50 w/o heart disease
(IC) Avoiding meat increases chances of avoiding heart disease
(C) People who want to reduce risk of heart disease shouldn't eat meat.

Correlation/Causation: just because 75% of vegetarians didn't have heart disease, does that mean that avoiding meat has anything to do with it? Maybe these 75% of vegetarians rigorously exercises everyday and drank red wine. This is what I am looking for. In addition, I also want some kind of recommendation in there.

(A) Discussion of a correlation (driving over speed limit) without discussion of causation ("driving over speed limit causes something"). Eliminate.

(B) Discussion of a correlation, check. Recommendation, check. However, the part that got me was "since cigarette smoking increases one's chances of incurring heart disease." This is not so much a conclusion about causation as it is just a given fact. This looks dicey.

(C) Missing assertion of causation. Eliminate.

(D) Missing assertion of causation. Eliminate.

(E) Correlation (exercise: stress), check. Discussion of causation (Exercising regularly → Decreases chances of stress), check. Recommendation, check.

This looks a bit better than (B) because it has more of an intermediate conclusion rather ("this shows that...") than another premise ("Since cigarette smoking...").

Otherwise, I think (B) and (E) are very similar.

How does that look?

Looks great.

[Mab6q]

I have a question about B. I read the claim "since cigarette smoking increases one's chances of incurring heart disease" as an intermediate conclusion extrapolated from the studies mentioned prior. Would you take that claim to be true, or should we treat it more like the intermediate conclusion in the original argument that concludes correlation from causation?


Thanks.

[maryadkins]

Good question.

It is actually an intermediate conclusion, and there is, as you note, a gap between the premise and it. So you could point out this gap as a logical problem.

[Mab6q]

Good question.

It is actually an intermediate conclusion, and there is, as you note, a gap between the premise and it. So you could point out this gap as a logical problem.

Let me follow up with another question if I may.

Let's say we have the following structure: A (premise), so B (intermediate conclusion), thus C (conclusion).

Now, say the relationship between B and C is flawed, but so is that between A and B, like this question. If we are asked to identify the flaw between B and C, we would take B to be true as a premise, right? Because we are no longer worried about B as a conclusion in the argument with A, but as a premise which concludes C, and the relationship between B and C is what's flawed.

I hope that made sense.

Thanks.

[tommywallach]

I think the answer to your question is "Yes, but they wouldn't do that." I've never seen a question with a flaw between the premise and the the intermediate conclusion AND between the intermediate conclusion and the main conclusion. And I hope I never do.

-t

[Mab6q]

I think the answer to your question is "Yes, but they wouldn't do that." I've never seen a question with a flaw between the premise and the the intermediate conclusion AND between the intermediate conclusion and the main conclusion. And I hope I never do.

-t

Haha me neither, but I'm trying to stretch these brain muscles.