Q18 - According to a government official involved in oversee

[slimjimsquinn]

Hello fellow LSAT peeps,

My breakdown of the stimulus goes as follows:

Premise : According to a government official, over 75% of the voice-recorder tapes taken from small airplanes involved in relatively minor accidents record the whistling of the pilot during the fifteen minutes immediately preceding the accident

Conclusion: Therefore, if passengers hear the pilot start to whistle they should take safety precautions


I sensed the central flaw has to do with failing to cite statistics for "the other group" (percentage of small airplane flights that did NOT result in minor accidents when the pilot whistled) but I was tempted by the other "statistical" sounding answer in E).

This seems to be a recurring problem for me. Can you tell me how to differentiate between the wrong and right statistical answer choices? Also, if there is a formal name for this flaw, how the test writers set it up, and what kind of answer will fix the flaw?

---
On another note, I want to thank all the teachers and fellow LSAT takers who post on this forum. Reading these posts have made so many concepts click for me; the language of your strategy guides and of the explanations on this forum are all so easy to understand. I've been flirting with workbooks from Princeton Review, used some Kaplan texts, and am taking a California-based prep company, but I'm finding that Manhattan LSAT is what clicks the most.

So, thank you! I read the teacher bios. You all seem like pretty interesting people. Thanks for lending a hand to us struggling test takers!

[timmydoeslsat]

Your understanding of the argument is correct.

We know that in 75% of tapes taken from small planes involved in minor accidents that pilots are heard whistling during the 15 minutes prior to the accident.

Should we really take precaution if we hear whistling?

Not really. We have not have not considered how often pilots whistle on flights in general. We have nothing to compare this statistic. Perhaps all pilots whistle all of the time in all planes. We are not considering the fact that whistling among pilots may be very common.

Answer choice E is not the flaw. Although it is true that the argument failed to tell us the % of all small airplane flights involved in minor accidents, we do not know whether the whistling aspect is occurring in a great number of these small flights involved in accidents.

Our flaw is concerned with the phenomenon of whistling and why that does not have to indicate nervousness on our part.

[tzyc]

I'm still not sure why (E) is wrong...
Actually I thought both (D) and (E) are needed to believe its conclusion because if we do not know the overall number and the percentage of the accident we cannot conclude what the argument concludes...why only (D) is enough for counter the conclusion??

Thank you!

[rinagoldfield]

Here’s the premise: 75% of pilots whistled before their planes got into minor accidents.

Here’s the conclusion: Whistling pilots are dangerous! Passengers should take safety precautions if they hear their pilot whistling.

But in order to connect whistling with danger, we need to know that a 75% whistling rate is unusually high. The argument offers no such evidence. Maybe 75% of pilots whistle on all flights. Or maybe 95% of pilots whistle on non-accident-bound flights. In either of these cases, whistling would be a very poor indicator of an upcoming accident.

The argument’s big flaw is that it assumes that whistling predicts accidents. But we need to contextualize the 75% whistling rate on accident-bound planes to know whether or not this is the case.

We’re looking for this vulnerability in the answer choices.

(A) doesn’t address the gap in the argument. Instead, it attempts to undermine the premise. Never undermine premises! Eliminate (A).
(B) is out of scope (where did that 1/4 statistic come from?) and doesn’t identify a weakness in the argument.
(C) only deals with the premise, and doesn’t identify a relevant weakness. We’re looking to connect whistling and accidents; the precise magnitude of the accident is irrelevant.
(D) is correct! This is just the context we need.
(E) is tempting... but we don’t actually need to know this. It doesn’t matter if 10% or 80% of flights end up in minor accidents. It only matters whether the 75% whistling rate on accident-bound planes is unusual.

[Mab6q]

Hey Manhattan experts,

I was wondering if you take a second to look at a question that is used in you LR book to demonstrate causal flaws that occur on the LSAT and how to tackle them. I believe the explanation in the book makes a mistake, one that I will try my best to demonstrate in my post. The question is PT 14, S 4, Q 18. I looked over the explanations on the forums and my question was not answered.

The argument talks about the whistling and minor accidents on small airplanes.

Conclusion: if passengers hear the pilot start to whistle, they should take take safety precautions.

WHY: according to government official last year, 75 percent of voice recorder takes taken from small airplanes involved in minor accidents record the whistling of the pilot 15 minutes prior to the accident.

Reasoning issues:

This is a terrible argument. One could point to minor issues, such as whether or not the voice recorders were on all of the airplanes that were involved in such accidents, but the major gap here is the causation issue. We don't know that the whistling ensured that the accidents were going to occur. Maybe it was the case, as your book suggests, that when the pilots get bored, they start whistling and get into accidents. That, however, would not mean that hearing whistling means that there will be an accident.

The correct answer choice here appears to be D. In the book, you guys write: "imagine that 75% of pilots just happen to always whistle while they fly. If that's the case, the author could'nt make the case that hearing whistling increases the likelihood of being in an accident." I agree, we do need D, but dont we need additional information as well!

Consider this:

1. 75% of time pilots whistle (per your hypo). Here, 75% of all flights involve the pilot whistling. What does this tell us? Absolutely nothing if we don't know what proportion of this are flights that resulted in minor accidents. Let's say all 75% percent of flights where the pilot whistles results in minor accidents. If that's the case, the author's conclusion is looking good. If only 1% of the 75% involves minor accidents, then that hurts the argument. However, all D tells us is what percentage we have whistling.

2. 50% of time pilots whistle. Here, we know that in half of all flights, the pilots whistle. Okay, so what. We still don't know anything about how many of these flights where the author whistles result in a minor accident. Let's say all of them do, that would be beneficial to the author. On the other hand let's say only 1% of this 50% percent are cases where there is a small accident, this would weaken the argument. However, we can't infer either of these choices through D alone.

3. 25% of time pilots whistle. Here we know that only in a quarter of all small airplane flights are pilots whistling. How does that help us? It dosent at all. It could be that all such cases occur when there is a minor accident. That is, all 25 percent of such flight's where the pilots whistle result in minor accident It's true than we would still have a stronger correlation here, but my point is that D, by itself, is insufficient.

Sorry for the redundancy but I really believe the LSAT made a mistake here. I know you probably might be thinking that D is still the best answer we have. However, the same issue arises in E, and it's just as good or just as bad as D, however way you want to look at it.

In the book, you guys write: "this answer choice is about the percentages of small airplane flights that involve minor accidents. Whether this percentage is .1% or 90%, it dosent impact the relationship between whistling and the likelihood of getting in an accident."

I would respectfully have to disagree.

Let me give you a similar hypo for E. Please bear with me.

1. 1% of flights result in minor accidents - Here, if we had 1000 flights, only 10 resulted in accidents. We can't make any kind of inference because we don't know the overall number of flights where the pilots whistled and there was an accident. If the pilot whistled in 1 percent of all flights, but it was that one percent where we had accidents, than the author's point is strengthened ( here there would be 7.5 cases where we had whistling and an accident, per the original premise). However, without the additional piece of evidence it's useless.

2. 99% of flights result in minor accidents - Here, if we had 1000 flights, 990 would have resulted in minor accidents. If we knew that 990 flights resulted in accidents, and of these 75 % (per the original premise) involved whistling, that would mean we had 742.5/1000 cases where there was whistling and a minor accident. That means 74% of the time when there was whistling there was an accident. This strengthens the argument without having the extra piece of information that we needed in the first example (knowing how many of the cases where we had whistling resulted in accidents).

THE POINT: My point here is not that the examples I gave strengthen the argument or provided more correlation to the causal claim; my point is that if we go based off why D is right, than E is just as good of an answer, IF NOT BETTER, due to the 99% example I just gave.

I hope you are still reading by now and that you understand my frustration with this problem. Can you please try to provide some clarity to this question. Isn't it inherently flawed by way of it's answer choices? How can D by itself be the correct answer choices if it requires more information, just as E does?

[WaltGrace1983]

1. 75% of time pilots whistle (per your hypo). Here, 75% of all flights involve the pilot whistling. What does this tell us? Absolutely nothing if we don't know what proportion of this are flights that resulted in minor accidents. Let's say all 75% percent of flights where the pilot whistles results in minor accidents. If that's the case, the author's conclusion is looking good. If only 1% of the 75% involves minor accidents, then that hurts the argument. However, all D tells us is what percentage we have whistling.

2. 50% of time pilots whistle. Here, we know that in half of all flights, the pilots whistle. Okay, so what. We still don't know anything about how many of these flights where the author whistles result in a minor accident. Let's say all of them do, that would be beneficial to the author. On the other hand let's say only 1% of this 50% percent are cases where there is a small accident, this would weaken the argument. However, we can't infer either of these choices through D alone.

3. 25% of time pilots whistle. Here we know that only in a quarter of all small airplane flights are pilots whistling. How does that help us? It dosent at all. It could be that all such cases occur when there is a minor accident. That is, all 25 percent of such flight's where the pilots whistle result in minor accident It's true than we would still have a stronger correlation here, but my point is that D, by itself, is insufficient.

This is EXACTLY why D is right. We NEED the information to make OR break the argument. We NEED to know THIS information in order to say, "okay, author, you ARE right" or "okay, author, you ARE NOT right."

Is #18's argument sufficient? No! Of course not! It is, after all, the LSAT. Well why not? Because it doesn't include the information you stated - for better or worse.

[WaltGrace1983]

Unless my understanding is insufficient, we are not trying to BREAK the argument in flaw questions. We are trying to show why the argument is lacking.

[Mab6q]

Thanks for responding WaltGrace. So you're saying that we NEED D, I guess we could consider it a necessary condition for the argument?

[WaltGrace1983]

Thanks for responding WaltGrace. So you're saying that we NEED D, I guess we could consider it a necessary condition for the argument?

I don't necessarily know if I would say that. "Provides no information about the %..." is NOT a necessary assumption. However, in order to make this argument, I guess it would be necessary to conclude something about the incidence of whistling and accidents.

I think a valid necessary assumption might be:

(D) Pilots do not whistle on every flight regardless of whether or not that flight makes it to its destination.

That might be a stretch though.

Here's the thing. (E) isn't right because we don't care about comparing (successful airplane flights) to (unsuccessful airplane flights) in a vacuum. Let's say that 99% of small airplane flights are successful; in other words, they don't have an accident. But so what? What does that tell us in regards to the argument?

Nothing. This is because we don't know anything about the whistling. The argument is basically a correlation/causation issue. The correlation is that 75% of small accidents are correlated with whistling. Thus, the author concludes that whistling will signal danger. In other words, (whistling --> danger).

How could we attack this argument? We show that whistling does not necessarily mean danger. This is what (D) says. (D) says, "Whoa! Wait up! We don't know about the other half! We need to know if whistling is also correlated with safe flights! If it is, then this argument makes no sense. If it isn't, then this argument is strengthened. Either way, we need to know this.

So the flaw answer choice is not necessarily strengthening or weakening the argument, nor is it giving a necessary assumption or a sufficient assumption. It is merely showing where the hole is. It is not even necessarily trying to fill it. The flaw is just showing where it is.

[mengyue.zhao]

Trying to simplify the explanation for why E is not correct.

I see "even such minor accidents pose some safety risk" as the second premise.

E : "fails to specify the percentage of all small air plane flights that involve relatively minor accidents"
-->if the percentage is small, it implies, legitimately or not, that the accidents should be less of a safety concern.

Thus E is trying to undermine the second premise.

Premise undermining should not be a correct answer.

[EmilyS251]

Hey Manhattan experts,

I was wondering if you take a second to look at a question that is used in you LR book to demonstrate causal flaws that occur on the LSAT and how to tackle them. I believe the explanation in the book makes a mistake, one that I will try my best to demonstrate in my post. The question is PT 14, S 4, Q 18. I looked over the explanations on the forums and my question was not answered.

The argument talks about the whistling and minor accidents on small airplanes.

Conclusion: if passengers hear the pilot start to whistle, they should take take safety precautions.

WHY: according to government official last year, 75 percent of voice recorder takes taken from small airplanes involved in minor accidents record the whistling of the pilot 15 minutes prior to the accident.

Reasoning issues:

This is a terrible argument. One could point to minor issues, such as whether or not the voice recorders were on all of the airplanes that were involved in such accidents, but the major gap here is the causation issue. We don't know that the whistling ensured that the accidents were going to occur. Maybe it was the case, as your book suggests, that when the pilots get bored, they start whistling and get into accidents. That, however, would not mean that hearing whistling means that there will be an accident.

The correct answer choice here appears to be D. In the book, you guys write: "imagine that 75% of pilots just happen to always whistle while they fly. If that's the case, the author could'nt make the case that hearing whistling increases the likelihood of being in an accident." I agree, we do need D, but dont we need additional information as well!

Consider this:

1. 75% of time pilots whistle (per your hypo). Here, 75% of all flights involve the pilot whistling. What does this tell us? Absolutely nothing if we don't know what proportion of this are flights that resulted in minor accidents. Let's say all 75% percent of flights where the pilot whistles results in minor accidents. If that's the case, the author's conclusion is looking good. If only 1% of the 75% involves minor accidents, then that hurts the argument. However, all D tells us is what percentage we have whistling.

2. 50% of time pilots whistle. Here, we know that in half of all flights, the pilots whistle. Okay, so what. We still don't know anything about how many of these flights where the author whistles result in a minor accident. Let's say all of them do, that would be beneficial to the author. On the other hand let's say only 1% of this 50% percent are cases where there is a small accident, this would weaken the argument. However, we can't infer either of these choices through D alone.

3. 25% of time pilots whistle. Here we know that only in a quarter of all small airplane flights are pilots whistling. How does that help us? It dosent at all. It could be that all such cases occur when there is a minor accident. That is, all 25 percent of such flight's where the pilots whistle result in minor accident It's true than we would still have a stronger correlation here, but my point is that D, by itself, is insufficient.

Sorry for the redundancy but I really believe the LSAT made a mistake here. I know you probably might be thinking that D is still the best answer we have. However, the same issue arises in E, and it's just as good or just as bad as D, however way you want to look at it.

In the book, you guys write: "this answer choice is about the percentages of small airplane flights that involve minor accidents. Whether this percentage is .1% or 90%, it dosent impact the relationship between whistling and the likelihood of getting in an accident."

I would respectfully have to disagree.

Let me give you a similar hypo for E. Please bear with me.

1. 1% of flights result in minor accidents - Here, if we had 1000 flights, only 10 resulted in accidents. We can't make any kind of inference because we don't know the overall number of flights where the pilots whistled and there was an accident. If the pilot whistled in 1 percent of all flights, but it was that one percent where we had accidents, than the author's point is strengthened ( here there would be 7.5 cases where we had whistling and an accident, per the original premise). However, without the additional piece of evidence it's useless.

2. 99% of flights result in minor accidents - Here, if we had 1000 flights, 990 would have resulted in minor accidents. If we knew that 990 flights resulted in accidents, and of these 75 % (per the original premise) involved whistling, that would mean we had 742.5/1000 cases where there was whistling and a minor accident. That means 74% of the time when there was whistling there was an accident. This strengthens the argument without having the extra piece of information that we needed in the first example (knowing how many of the cases where we had whistling resulted in accidents).

THE POINT: My point here is not that the examples I gave strengthen the argument or provided more correlation to the causal claim; my point is that if we go based off why D is right, than E is just as good of an answer, IF NOT BETTER, due to the 99% example I just gave.

I hope you are still reading by now and that you understand my frustration with this problem. Can you please try to provide some clarity to this question. Isn't it inherently flawed by way of it's answer choices? How can D by itself be the correct answer choices if it requires more information, just as E does?

I was struggling with this question and I agree with your logic. Both D and E are technically needed in order to calculate the probability that an accident will occur given that a pilot is whistling. This is a probability question that could be modelled by Bayes Theorem. I really struggled with this due to some knowledge of statistics. However, I think that the LSAT assumes that the incidence of small accidents is relatively low ("Even such minor accidents pose some safety risk") in which case the argument is compelling only if a pilot whistling is a rare occurrence in general, information which is not provided in the stimulus. E is not incorrect, it's just less correct than D (the question stem says "the argument is MOST vulnerable...").