Sections 3

LSAT 111 - Section 3 - Question 13

October 12, 2012

President of the Regional Chamber of Commerce: We are all aware of the painful fact that almost no new businesses have moved into our region or started up here over the last ten years. But the Planning Board is obviously guilty of a gross exaggeration in its recent estimate that businesses are leaving the region at the rate of about four a week. After all, there were never more than about one thousand businesses in the region, so if they were really leaving at such a rate, they would all have been gone long ago.

Summarize Argument

The president claims the Planning Board's estimate that businesses are leaving the region at a rate of four per week is an exaggeration. He supports this by saying that since there were never more than about a thousand businesses in the region, and no new businesses have moved in over the last ten years, they would have all disappeared by now if that estimate were accurate.

Identify and Describe Flaw

The president assumes that the Planning Board’s estimate has been the case for a long period of time. But just because business are leaving the region at a rate of four per week doesn’t mean that they have been leaving at this rate for many months or years. If business only started leaving at this rate very recently, the president’s argument falls apart.

A

focuses on what is going out of a system while ignoring the issue of what is coming into the system

The president doesn’t ignore the issue of what’s coming into the system. In fact, he explicitly states that “almost no new businesses have moved into our region or started up here over the last ten years.”

B

confuses a claim about a rate of change within a system with a claim about the absolute size of the system

The argument addresses a claim about the rate of change and a claim about the absolute size of the system, but the president doesn’t confuse these claims. Instead, he uses a claim about absolute size to refute the claim about the rate of change.

C

argues against a position simply by showing that the position serves the interest of the Planning Board

The president never claims that the Planning Board’s estimate serves their own interest.

D

treats a claim about what is currently the case as if it were a claim about what has been the case for an extended period

The president treats the claim that businesses are currently leaving the region at a rate of four per week as if it has been the case for an extended period of time. But perhaps businesses only began leaving at that rate very recently. If so, the president’s argument falls apart.

E

attacks what was offered as an estimate on the ground that it is not precise

The president never attacks the precision of the Planning Board’s estimate. Instead, he claims that the estimate is exaggerated.

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LSAT 31 - Section 3 - Question 09

October 12, 2012

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LSAT 113 - Section 3 - Question 20

October 12, 2012

One of the most vexing problems in historiography is dating an event when the usual sources offer conflicting chronologies of the event. Historians should attempt to minimize the number of competing sources, perhaps by eliminating the less credible ones. Once this is achieved and several sources are left, as often happens, historians may try, though on occasion unsuccessfully, to determine independently of the usual sources which date is more likely to be right.

Summary

One of the most challenging problems in historiography is dating an event when sources offer conflicting information. Historians should minimize the number of these sources by eliminating less credible ones. Once this happens, historians should try to determine independently which of the sources is most likely to be right, although they are sometimes unsuccessful.

Strongly Supported Conclusions

There are some events that historians have not reliably dated.

A

We have no plausible chronology of most of the events for which attempts have been made by historians to determine the right date.

This is too broad to support. There is not enough support to contend that we have no plausible chronology of “most” disputed events. The stimulus says that historians were unable to successfully date *some* events.

B

Some of the events for which there are conflicting chronologies and for which attempts have been made by historians to determine the right date cannot be dated reliably by historians.

The stimulus says that historians “on occasion unsuccessfully” try to determine the date for an event after minimizing competing sources. This implies that there are at least some events that cannot be dated reliably.

C

Attaching a reliable date to any event requires determining which of several conflicting chronologies is most likely to be true.

This is too broad to support. The stimulus only concerns dates where the usual sources offer conflicting information, not “any event.”

D

Determining independently of the usual sources which of several conflicting chronologies is more likely to be right is an ineffective way of dating events.

This is antisupported. The stimulus suggests this method to date events.

E

The soundest approach to dating an event for which the usual sources give conflicting chronologies is to undermine the credibility of as many of these sources as possible.

This is too strong to support. The stimulus says that this is *an* approach, not that this is the *soundest* or best approach. Be wary of these strong words in answer choices! They can sometimes be supported, but make sure to double-check the stimulus for the support.

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LSAT 31 - Section 3 - Question 07

October 12, 2012

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LSAT 111 - Section 3 - Question 09

October 4, 2012

A running track with a hard surface makes for greater running speed than a soft one, at least under dry conditions, because even though step length is shorter on a hard surface, the time the runner’s foot remains in contact with the running surface is less with a hard surface.

Summarize Argument

The author concludes that a hard track allows for faster running than a soft track, provided the conditions are dry. Why? Because on a hard track, runners spend less time with their feet touching the ground, even though their steps are shorter.

Notable Assumptions

The author assumes that runners save more time by keeping their feet off the ground than they lose by taking shorter steps on a hard track. In addition, he assumes there’s no other feature of hard tracks that allows people to run faster on them.

A

Dry running conditions can be guaranteed for indoor track races only.

This implies the conclusion isn’t always relevant, not that the argument is incomplete. The author restricts his statements to dry tracks only.

B

In general, taller runners have greater average step length than shorter runners do.

This doesn’t say shorter runners would benefit from a softer track, because it’s possible the shorter step length allowed by the harder surface holds back runners of all heights equally.

C

Hard tracks enhance a runner’s speed by making it easier for the runner to maintain a posture that minimizes wind resistance.

This calls the argument into question even though it gives another reason to support the conclusion. Perhaps hard tracks make for faster running because they reduce wind resistance, not because they allow for more air time.

D

The tracks at which the world’s fastest running times have been recorded are located well above sea level, where the air is relatively thin.

This suggests elevation is another factor that can affect running speed, but gives no difference between hard and soft tracks suggesting the reasoning is incomplete. The author does not claim that track surface is the only variable that might affect running speed.

E

To remain in top condition, a soft track surface requires different maintenance procedures than does a hard one.

This doesn’t say a soft track is any more or less likely to remain in top condition, nor what effect a track in poor condition would have on running speed.

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LSAT 107 - Section 3 - Question 22

October 4, 2012

Biologist: Some speculate that the unusually high frequency of small goats found in island populations is a response to evolutionary pressure to increase the number of goats so as to ensure a diverse gene pool. However, only the reproductive success of a trait influences its frequency in a population. So, the only kind of evolutionary pressure that can reduce the average size of the members of a goat population is that resulting from small goats achieving greater reproductive success than their larger cousins.

Summary

The biologist refutes the view that the high frequency of small goats on islands is due to evolutionary pressure to increase the number of goats. Why is this wrong? The only way a trait can increase in frequency is through reproductive success, Therefore, the only evolutionary pressure that could cause this phenomenon is small goats achieving greater reproductive success.

Strongly Supported Conclusions

The biologist considers the speculations she refers to to be incorrect.

Small goats have greater reproductive success in island populations than larger goats.

Ensuring a diverse gene pool does not qualify as evolutionary pressure.

A

The evolutionary pressure to ensure a diverse gene pool could have the effect of increasing the frequency of a gene for small size.

Anti-supported. The biologist refutes this point. She says only reproductive success would qualify as evolutionary pressure.

B

The unusual frequency of small goats in island populations is not a result of the greater reproductive success small goats possess when space is limited.

Anti-supported. The biologist claims that the only thing that can reduce the average size of the population is greater reproductive success for small goats. This may or may not be due to the small space.

C

Contrary to what some believe, large goats achieve greater reproductive success than small goats even when space is limited.

Unsupported. There is no support for the actual reproductive success rates by goat size. The biologist is advocating the point that the smaller goats must achieve greater reproductive success in order to decrease the average size of the goats.

D

The evolutionary pressure to ensure a diverse gene pool does not have the effect of increasing the frequency of a gene for small size.

Strongly supported. The author dismisses this claim on the grounds that it does not impact reproductive success, the only way to influence frequency. Therefore, ensuring a diverse gene pool cannot have the effect of increasing the frequency of the gene for small size.

E

A diverse gene pool cannot be achieved in a goat population unless the average size of its members is reduced.

Unsupported. There is no information as to how a diverse gene pool can or cannot be achieved. That was only part of a theory that was dismissed.

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LSAT 26 - Section 3 - Question 15

October 4, 2012

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LSAT 103 - Section 3 - Question 15

October 4, 2012

A person’s dietary consumption of cholesterol and fat is one of the most important factors determining the level of cholesterol in the person’s blood (serum cholesterol). Serum cholesterol levels rise proportionally to increased cholesterol and fat consumption until that consumption reaches a threshold, but once consumption of these substances exceeds that threshold, serum cholesterol levels rise only gradually, even with dramatic increases in consumption. The threshold is one fourth the consumption level of cholesterol and fat in today’s average North American diet.

Summary

A person’s consumption of cholesterol and fat is one of the most important factors affecting a person’s serum cholesterol level. Serum cholesterol levels increase proportionally to increased consumption of fat and cholesterol until a threshold is reached. Once this threshold is reached, consumption of fat and cholesterol only cause a person’s serum cholesterol level to rise gradually even if consumption of fat and cholesterol increases dramatically. The threshold is one fourth the consumption level of these substances in the average North American diet.

Strongly Supported Conclusions

A person who consumes a fraction of the amount of cholesterol and fat compared to the average North American may not have a significantly different level of serum cholesterol.

A

The threshold can be lowered by lowering the dietary consumption of cholesterol and fat.

This answer is unsupported. We don’t know what factors could cause the threshold to be lowered, if at all.

B

People who consume an average North American diet cannot increase their consumption of cholesterol and fat without dramatically increasing their serum cholesterol levels.

This answer is anti-supported. We know that once a threshold is reached, dramatic increases in the consumption of cholesterol and fat can only result in a gradual increase of serum cholesterol.

C

People who consume half as much cholesterol and fat as in the average North American diet will not necessarily have half the average serum cholesterol level.

This answer is strongly supported. If a person is consuming half as much cholesterol and fat than the average North American, then that person is still consuming double the the amount of these substances compared to the threshold.

D

Serum cholesterol levels cannot be affected by nondietary modifications in behavior, such as exercising more or smoking less.

This answer is unsupported. We only know that consumption of cholesterol and fat is one of the most important factors affecting serum cholesterol. It is possible that there are other factors that could affect serum cholesterol levels.

E

People who consume less cholesterol and fat than the threshold cannot reduce their serum cholesterol levels.

This answer is anti-supported. We know from the stimulus that, before a threshold, serum cholesterol levels are directly proportional to a person’s consumption of fat and cholesterol.

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LSAT 33 - Section 3 - Question 14

September 13, 2012

This is an Argument Part question, so we have to describe the role played in the argument by the statement that "many major cities had similar ratios of police officers to citizens, yet diverged widely in their crime rates."

Like all other LR questions, we try to identify the conclusion and the premises first.

This passage is sneaky. It start by telling us that "many people believe X". Normally, when we encounter a passage that starts like that, what's the upshot? What's the conclusion?

That those people are wrong in their moronic beliefs.

I mean, if I just told you "Look man, I know that lots of people believe X, but Y". You actually get a lot of information out of this right?

You must hear me communicating to you that those people are wrong. The structuring of that sentence, using "but" says that much.

In this passage, we're suppose to hear that increasing the number of police officers is not the only way to remedy crime. That's the unspoken conclusion.

Why should we believe it?

Just look at all these major cities with about the same number of cops to citizens (say, 1 cop for every 1,000 citizens). Yet, they all have very different levels of crime.

We are prodded to draw the conclusion that there must be some other factor that influence the level of crime. In other words, number of cops isn't the only factor. That's answer choice (E).

(C) is wrong because it's not clear what counts as a "proof". If they mean validity, then certainly this argument doesn't meet that high standard. Additionally, (C) says there are other factors that are "more important" than the number of cops. We have some information that there exists other factors, maybe. But we have no information about the relative causal strength of those factors. Which one is more important?

(D) is wrong because the idea of "having no effect" is very different from the idea of "being one causal component amongst many".

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LSAT 109 - Section 3 - Question 14

September 13, 2012

Many people think that the only way to remedy the problem of crime is by increasing the number of police officers, but recent statistics show that many major cities had similar ratios of police officers to citizens, yet diverged widely in their crime rates.

Summarize Argument: Counter-Position

The author seems to disagree with people who think that increasing police numbers is the only way to reduce crime. There’s no outright statement of disagreement, but the rest of the argument proceeds as though disputing those people’s view. Specifically, the author cites statistical evidence: various cities with similar police-to-population ratios have very different crime rates. This leads to the implied conclusion that boosting police numbers isn’t the only way to lower crime rates.

Identify Argument Part

The statistics cited in the argument are support (i.e. a premise) for the implicit conclusion that it is not the case that increasing police numbers is the only way to solve crime.

A

establish that the number of police officers does not need to be increased

Like (B), the author never takes a stance on whether or not police numbers need to be increased. The argument doesn’t do this, and nor does any part of it.

B

illustrate the need for increasing the number of police officers in major cities

Like (A), the author never offers a suggestion on whether police numbers should or shouldn’t be increased, in major cities or anywhere else. This isn’t in the argument at all.

C

prove that there are factors other than the number of police officers that are more important in reducing the crime rate

The author doesn’t say anything about whether other factors are more important than the number of police in reducing crime. The argument is just meant to suggest that other factors make a difference, not say which is most important.

D

demonstrate that there is no relation between the number of police officers and the crime rate

The author never denies that police numbers make a difference to crime rates, just that they’re the single, only factor. The statistics suggest that something else might also contribute to lowering crime rates, not that police numbers are irrelevant.

E

suggest that the number of police officers is not the only influence on the crime rate

This correctly identifies that the statistics act as a premise to support the conclusion that factors other than police numbers could help to address crime.

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