A
The volume of freight shipped by rail can be expected to increase.
B
Increasing reliance on automation means that fewer railroad workers are needed.
C
No reduction in operating costs is predicted for the trucking industry.
D
Operating costs for railroads have been reduced as a result of increased reliance on automation.
E
The chief competitor of railway shipping is shipping by truck.
A
Boiled cow’s milk makes less vitamin C available to infants than does the same amount of mother’s milk.
B
Infants who consume cow’s milk that has not been boiled frequently contract potentially fatal gastrointestinal infections.
C
Mother’s milk can cause gastrointestinal infections in infants.
D
When doctors advised that cow’s milk fed to infants should be boiled, they did not know that scurvy was caused by vitamin C deficiency.
E
When doctors advised that cow’s milk fed to infants should be boiled, most mothers did not breast-feed their infants.
A
Fire departments tend to receive less funding during periods of severe drought than during periods of normal rainfall.
B
Areas subject to grass and brush fires tend to be less densely populated than areas where there are few such fires.
C
Unusually large, hard-to-control grass and brush fires typically occur only when there is a large amount of vegetation for them to consume.
D
Grass and brush fires that are not caused by human negligence or arson tend to be started by lightning.
E
When vegetation is destroyed in a grass or brush fire, it tends to be replaced naturally by vegetation that is equally if not more flammable.
This is a Weakening question.
In Weakening questions, we take away the support that the premise provides to the conclusion. We usually do this by identifying an assumption in the argument and stating the opposite of that assumption.
The stimulus says that the government’s tax collection agency (i.e., IRS) has not followed through on its plan, announced a year ago, to crack down on violations of corporate income tax law. This is the conclusion. And the premise for this conclusion is that audits are the primary tool for detecting such violations, and over the past year, not a single audit of corporate income tax returns has been completed.
So far, it sounds like the IRS is doing a pretty bad job following through on its plan. But wait, we’re not supposed to like this argument. We’re supposed to identify where this argument is weak.
If you feel this way at the end of a stimulus, that’s okay. Just remind yourself to be skeptical and then look at the answer choices. Perhaps one of them will clue you in on where the argument is weak.
Answer Choice (A) says the plan to crack down on violations of corporate income tax law is part of a broader campaign against corporate misconduct. So who cares if some other agencies like the SEC or the FTC also announced their plans? We are discussing whether the IRS followed through on its plan, so (A) is entirely irrelevant.
Answer Choice (B) says the number of personal income tax returns audited over the past year is greater than in previous years. There is a big difference between corporate income tax and personal income tax, which makes (B) irrelevant. While (B) might become more relevant if you misread personal as corporate, (B) is useless as it currently stands.
Answer Choice (C) says most audits of corporate income tax returns do not reveal any significant violations. All (C) tells us is that, of the set of all audits of corporate income tax returns, only a minority revealed significant violations. How does this information even fit into the stimulus? It still stands that zero audits were completed last year.
Answer Choice (D) says it generally takes longer than one year to complete an audit of a corporate income tax return. This reveals the naive assumption the argument made. For example, if it only takes three months to complete an audit and the IRS had completed zero audits, we can say it did not follow through on its plan. However, if it takes more than a year to complete an audit, the IRS could have followed through on its plan by having initiated many audits in the past year even though none were completed.
While the information in (D) does not challenge the truth of the premise, it changes its significance. The fact that the IRS had completed zero audits now has no power to show that it did not follow through on its plan. This a quintessential correct answer choice in a Weakening question. (D) does not challenge the truth of the premise or the conclusion, but it does weaken the support that the premise gives to the conclusion.
Answer Choice (E) says that over the last five years, fewer audits of corporate income tax returns have been completed than in the preceding five years. (E) might relate to the argument by revealing the reason why the IRS said they were going to crack down on tax violations. They might have realized that they are auditing less than they used to and decided to pick up the pace. But even so, this does not weaken the argument.
This is a Flaw/Descriptive Weakening question.
The stimulus says that making some types of products from recycled materials is probably as damaging to the environment as it would be to make those products from entirely nonrecycled material. This is the conclusion. If we use soda cans as an example, making soda cans from recycled aluminum is just as damaging to the environment as making them from new aluminum.
Why is this so? The premise is that the recycling process for those products requires as much energy as producing them from raw materials, and almost all energy production damages the environment. Okay, so producing a recycled aluminum can and a new aluminum can are equally damaging to the environment in terms of energy production.
But does that mean they are equally damaging to the environment, period? What about the actual materials used? Surely we cannot assume that energy production is the only factor that determines environmental damage. The fact that a recycled can’s aluminum came from other cans and not aluminum mines has to count for something.
The reasoning here is cost-benefit analysis, and the author failed to consider other costs and benefits. The argument accounted for energy production as a component of environmental damage but forgot to account for other components. We’re not looking at causal reasoning.
Since we spotted the flaw, let’s turn to the answer choices.
Answer Choice (B) says that the argument treats an effect of energy-related damage as if it were instead the cause of such damage. What is the effect of energy-related damage? Maybe we will see 80-degree weather in New York on Christmas, but why is this relevant? The argument is not even close to a causal one and (B) does not describe the argument’s flaw.
Answer Choice (E) says that the argument presumes that simply because one phenomenon follows another, the earlier must be a cause of the later. Both (B) and (E) describe cookie-cutter flaws related to causation, and if such flaws were actually present in the argument, they would be the right answer choice. But (E) has nothing to do with this argument.
Answer Choice (A) says that the argument uses the word “environment” in one sense in the premise and in a different sense in the conclusion. (A) describes another cookie-cutter flaw that could be correct in other questions, but not in this one. It accuses the argument of having shifted the meaning of a key term or phrase, but it is clear that the premise and the conclusion are referring to the same concept of environment.
Answer Choice (C) says that the argument fails to consider that the particular types of recycled products that it cites may not be representative of recycled products in general. However, the columnist explicitly said making some types of products from recycled material is probably as damaging, not that recycling is just as damaging in general as making products from new materials. And surely the columnist never cited any particular types of products. While I used soda cans to illustrate the argument, the columnist’s argument was nonspecific.
Answer Choice (D) says that the argument fails to consider that making products from recycled materials may have environmental benefits unrelated to energy consumption. This successfully picks up on the accounting error we spotted earlier. This is a benefit of recycling that the argument failed to account for.
This is an Argument Part question.
We have to identify the role of the statement that “people who are constantly subjected to fire drills eventually come to ignore the fire alarm.”
The stimulus says that we are constantly bombarded by warnings, based on initial studies' tentative conclusions, about this or that food having adverse health effects. For example, we are warned that fat is good one day then bad the next, and these warnings are only based on initial studies' tentative conclusions.
Then it says that if the medical establishment wants people to pay attention to health warnings, it should announce only conclusive results, the kind that can come only from definitive studies. This is the conclusion. And why should we believe this? After all (this is a premise indicator), people who are constantly subjected to fire drills eventually come to ignore the fire alarm. This is the statement whose role we have to identify, and we have just identified that it is a premise.
But this is a premise that supports the conclusion via reasoning by analogy. Author says constantly bombarding people with health warnings is just like constantly subjecting people to fire drills. Constant fire drills only train people to ignore the fire alarm, and similarly, people are going to stop paying attention to health warnings if they are constantly bombarded by them.
Answer Choice (A) says that the statement is presented as an example of the sort of warning referred to in the argument's overall conclusion. It is not. Examples of such warnings would be warnings that are based on definitive studies such as three decades of nutritional studies that have conclusively shown that sugar above a certain amount is bad.
There is a big difference between examples and analogies. Examples are particular instances of generalities. Analogies come from a different set of generalities but share certain features we identify as similar.
Answer Choice (B) says that the statement plays no logical role but instead serves to impugn the motives of the medical establishment. The statement does play a logical role, and it does not impugn the motives of the medical establishment. Such a claim might be something like “the medical establishment receives a ton of funding from food companies that skew their incentives to do objective science.”
Answer Choice (C) says that the statement is an analogy offered in support of the argument's overall conclusion. Perfect.
Answer Choice (D) says that the statement is an analogy that forms part of a scientific objection to the argument's overall conclusion. While the analogy is an objection to something, it is definitely not an objection to the conclusion. Within the conclusion, there is an objection to bombarding people with health warnings. And the statement supports this objection, which means it is supporting the conclusion, not objecting to it.
Answer Choice (E) says that the statement is an analogy offered to clarify the distinction that the physician makes between an initial study and a definitive study. While the physician does make this distinction, a clarification of this distinction is never provided.
This is a Flaw/Descriptive Weakening question.
The stimulus says that a club wanted to determine whether it could increase attendance by changing its weekly meeting from Tuesday to another day. So at one Tuesday meeting, the club's president took a survey of all members present, and 95% said they had no difficulty attending on Tuesdays. The club president therefore concluded that the attendance problem was not due to scheduling conflicts.
This is strange. Why did the president survey the members already present at a Tuesday meeting on whether Tuesday is a good day? They already showed up to the meeting, so Tuesday is obviously a convenient day for them. And while you can say that the Tuesday meeting was not an issue for the Tuesday attendees, you cannot draw the same conclusion about all members. This is the big flaw in the argument. The members present on Tuesday are an unrepresentative sample, and they specifically do not represent the people who were not present on Tuesday.
Here is a helpful analogy. Say I am an ice cream shop owner who only sells vanilla ice cream and I want to increase my revenue by possibly changing my flavor to chocolate or strawberry. So I survey all of my customers and 95% say they have no problem with the vanilla flavor. I therefore decide that my revenue problem is not due to the flavoring of the ice cream. What a silly argument, right? I am asking people who are already buying my vanilla ice cream if vanilla flavor is the issue. The customers surveyed are not representative of people who are not yet my customers.
Answer Choice (B) says that the reasoning makes a generalization on the basis of a sample that is likely to be unrepresentative. (B) picks up on the cookie-cutter flaw above. The club president makes a generalization about all members on the basis of an unrepresentative sample, the members who had no problem showing up on Tuesdays.
Answer Choice (A) says that the reasoning draws a conclusion on the basis of circular reasoning. This is not an instance of circular reasoning. Circular reasoning has conclusions and premises that effectively say the same thing, such as “I am the best because no one in the world is better than me.”
If you picked (A), you might have thought that the argument uses circular reasoning because of the repeated use of Tuesday meeting attendance. However, circular reasoning would look something like “the attendance problem is not due to scheduling conflicts because scheduling conflicts do not create attendance problems.” The stimulus instead has distinct premise and conclusion claims.
Answer Choice (C) says that the reasoning treats a generalization that applies to most cases as if it applied without exception. But the conclusion explicitly accounts for possible exclusions because it says the attendance problem was not due primarily to scheduling conflicts. For (C) to be correct, the argument would have to say that since most members of our club said that weekend meetings are okay, weekend meetings are okay for everybody in our club.
Answer Choice (D) says the reasoning draws a conclusion on the basis of premises that contradict one another. The stimulus does draw a conclusion, but there are no premises that contradict one another.
To contradict the first premise, we have to say that a club does not want to figure out if it could increase attendance by changing its weekly meeting. To contradict the next premise, we have to say that at one Tuesday meeting, the club president did not take a survey. To contradict the last premise, we have to say that of those surveyed, 95% said that they did have difficulty with a Tuesday meeting. None of these contradictory statements are present in the stimulus.
Answer Choice (E) is the oldest mistake in the book. It says that the club president’s reasoning is inferring, solely from the claim that a change is not sufficient to solve a problem, that it is not necessary either.
Let's illustrate what the argument would have to look like for (E) to be correct. A club has decided that it wants to double its attendance. It realized that if they move their meetings from Tuesdays to Fridays, their attendance will increase by only 10%. Since this change is not sufficient, it concluded that it is not necessary either.
That’s sufficiency necessity confusion. It’s a flaw because it’s possible that moving the meeting to Friday, while insufficient, is actually necessary. For example, perhaps providing free beer on Fridays will supply the remaining 90% increase. While neither change is independently sufficient, both are necessary.
This is a Weakening question.
In Weakening questions, we take away the support that the premise provides to the conclusion. We usually do this by identifying an assumption in the argument and stating the opposite of that assumption.
The stimulus says that the government’s tax collection agency (i.e., IRS) has not followed through on its plan, announced a year ago, to crack down on violations of corporate income tax law. This is the conclusion. And the premise for this conclusion is that audits are the primary tool for detecting such violations, and over the past year, not a single audit of corporate income tax returns has been completed.
So far, it sounds like the IRS is doing a pretty bad job following through on its plan. But wait, we’re not supposed to like this argument. We’re supposed to identify where this argument is weak.
If you feel this way at the end of a stimulus, that’s okay. Just remind yourself to be skeptical and then look at the answer choices. Perhaps one of them will clue you in on where the argument is weak.
Answer Choice (A) says the plan to crack down on violations of corporate income tax law is part of a broader campaign against corporate misconduct. So who cares if some other agencies like the SEC or the FTC also announced their plans? We are discussing whether the IRS followed through on its plan, so (A) is entirely irrelevant.
Answer Choice (B) says the number of personal income tax returns audited over the past year is greater than in previous years. There is a big difference between corporate income tax and personal income tax, which makes (B) irrelevant. While (B) might become more relevant if you misread personal as corporate, (B) is useless as it currently stands.
Answer Choice (C) says most audits of corporate income tax returns do not reveal any significant violations. All (C) tells us is that, of the set of all audits of corporate income tax returns, only a minority revealed significant violations. How does this information even fit into the stimulus? It still stands that zero audits were completed last year.
Answer Choice (D) says it generally takes longer than one year to complete an audit of a corporate income tax return. This reveals the naive assumption the argument made. For example, if it only takes three months to complete an audit and the IRS had completed zero audits, we can say it did not follow through on its plan. However, if it takes more than a year to complete an audit, the IRS could have followed through on its plan by having initiated many audits in the past year even though none were completed.
While the information in (D) does not challenge the truth of the premise, it changes its significance. The fact that the IRS had completed zero audits now has no power to show that it did not follow through on its plan. This a quintessential correct answer choice in a Weakening question. (D) does not challenge the truth of the premise or the conclusion, but it does weaken the support that the premise gives to the conclusion.
Answer Choice (E) says that over the last five years, fewer audits of corporate income tax returns have been completed than in the preceding five years. (E) might relate to the argument by revealing the reason why the IRS said they were going to crack down on tax violations. They might have realized that they are auditing less than they used to and decided to pick up the pace. But even so, this does not weaken the argument.
This is a Flaw/Descriptive Weakening question.
The stimulus says that making some types of products from recycled materials is probably as damaging to the environment as it would be to make those products from entirely nonrecycled material. This is the conclusion. If we use soda cans as an example, making soda cans from recycled aluminum is just as damaging to the environment as making them from new aluminum.
Why is this so? The premise is that the recycling process for those products requires as much energy as producing them from raw materials, and almost all energy production damages the environment. Okay, so producing a recycled aluminum can and a new aluminum can are equally damaging to the environment in terms of energy production.
But does that mean they are equally damaging to the environment, period? What about the actual materials used? Surely we cannot assume that energy production is the only factor that determines environmental damage. The fact that a recycled can’s aluminum came from other cans and not aluminum mines has to count for something.
The reasoning here is cost-benefit analysis, and the author failed to consider other costs and benefits. The argument accounted for energy production as a component of environmental damage but forgot to account for other components. We’re not looking at causal reasoning.
Since we spotted the flaw, let’s turn to the answer choices.
Answer Choice (B) says that the argument treats an effect of energy-related damage as if it were instead the cause of such damage. What is the effect of energy-related damage? Maybe we will see 80-degree weather in New York on Christmas, but why is this relevant? The argument is not even close to a causal one and (B) does not describe the argument’s flaw.
Answer Choice (E) says that the argument presumes that simply because one phenomenon follows another, the earlier must be a cause of the later. Both (B) and (E) describe cookie-cutter flaws related to causation, and if such flaws were actually present in the argument, they would be the right answer choice. But (E) has nothing to do with this argument.
Answer Choice (A) says that the argument uses the word “environment” in one sense in the premise and in a different sense in the conclusion. (A) describes another cookie-cutter flaw that could be correct in other questions, but not in this one. It accuses the argument of having shifted the meaning of a key term or phrase, but it is clear that the premise and the conclusion are referring to the same concept of environment.
Answer Choice (C) says that the argument fails to consider that the particular types of recycled products that it cites may not be representative of recycled products in general. However, the columnist explicitly said making some types of products from recycled material is probably as damaging, not that recycling is just as damaging in general as making products from new materials. And surely the columnist never cited any particular types of products. While I used soda cans to illustrate the argument, the columnist’s argument was nonspecific.
Answer Choice (D) says that the argument fails to consider that making products from recycled materials may have environmental benefits unrelated to energy consumption. This successfully picks up on the accounting error we spotted earlier. This is a benefit of recycling that the argument failed to account for.