A new tax law aimed at encouraging the reforestation of cleared land in order to increase the amount of forested land in a particular region offers lumber companies tax incentives for each unit of cleared land they reforest. One lumber company has accordingly reduced its tax liability by purchasing a large tract of cleared land in the region and reforesting it. The company paid for the purchase by clearing a larger tract of land in the region, a tract that it had planned to hold in long-term reserve.

Summary
This new tax law intends to increase the amount of forested land in the region.
The law offers tax incentives for lumber companies for each unit of cleared land that they reforest.
A company purchased a large area of already cleared land and reforested it in order to receive the tax incentives.
The company paid for this purchase by clearing a larger tract of land in the region that it had originally planned to hold in long-term reserve.

Notable Valid Inferences
The tax law incentivized the lumber company to clear more land than it otherwise would have. In order to buy and reforest a large tract of cleared land, the company cleared an even larger tract of land that it had intended to hold in reserve. This is a net-loss in forested area.

A
It is a failure in encouraging the reforestation of cleared land in the region.
This could be false. This is too broad. The stimulus only discusses the actions of one company; we don’t know enough to say whether the new law was a failure overall. Further, in this case, the law actually did encourage the company to reforest a large tract of cleared land.
B
It will have no immediate effect on the amount of forested land in the region.
This could be false. Even in the example with the company, we can see that the law had an effect on the amount of forested land in the region (a net loss).
C
It will ultimately cause lumber companies to plant trees on approximately as much land as they harvest in the region.
This could be false. Since we only know about the actions of one company, we can’t make any definitive claims about what the ultimate result of the new law will be.
D
It can provide a motivation for companies to act in a manner contrary to the purpose of the law while taking advantage of the tax incentives.
This must be true. The law encouraged the company to act in a way that resulted in a net loss of forested area, even though the intent of the law was to increase the amount of forested land.
E
It will provide lumber companies with a tax incentive that will ultimately be responsible for a massive decrease in the number of mature forests in the region.
This could be false. Similar to (C), since we only have the description of the actions of one company, we can’t make any claims about what the overall results of the law will be.

6 comments

This is a pretty tough question. We're prone to understand the argument incorrectly.

The conclusion states that the museum's continued existence depended on the coverage from the local media. In other words, the local media's coverage was a necessary condition for the museum's being still open and in business.

Fair enough. Why should we believe this? One premise says that if there was low attendance at the recent exhibit then the museum would have closed. Okay, good. This means that a necessary condition of the museum staying open is medium-to-high level attendance at the recent exhibit.

Now, in order for the conclusion to follow, we simply need to show that coverage from the local media was the only thing responsible for medium-to-high level attendance.

Does the remaining premises show that? No. It says that local media coverage existed. It also says that local media coverage seems to have contributed to attendance. In other words, it seems to have been a causal factor.

Seems to have contributed? Did it contribute or not? Was it a causal factor or not? We don't know.

That's mistake #1.

Correcting for it, the premise still isn't good enough. The corrected version says that local media coverage contributed to attendance. We we needed it to say that local media coverage was the necessary cause for medium-to-high level attendance. Otherwise, why would the museum's existence depend on it? That's mistake #2.

As for (A), the "necessary condition" it's referring to is "medium-to-high level attendance at the recent exhibit." But the argument never mistook that for a sufficient condition. Did you?


11 comments

Economist: A tax is effective if it raises revenue and burdens all and only those persons targeted by the tax. A tax is ineffective, however, if it does not raise revenue and it costs a significant amount of money to enforce.

Summary

If a tax raises revenue and burdens only people targeted by the tax, then then tax is effective. If a tax does not raise revenue and it costs a significant amount of money to enforce, then the tax is ineffective.

Strongly Supported Conclusions

If a tax is ineffective, then it either does not raise revenue or it does not burden all and only people targeted by the tax.

A
The tax on cigarettes burdens most, but not all, of the people targeted by it. Thus, if it raises revenue, the tax is effective.

This answer is unsupported. This answer fails one of our sufficient conditions for a tax to be considered effective. We need both of the sufficient conditions in order for a tax to be considered effective.

B
The tax on alcohol raises a modest amount of revenue, but it costs a significant amount of money to enforce. Thus, the tax is ineffective.

This answer is unsupported. This answer fails one of our sufficient conditions for a tax to be considered ineffective. We need both of the sufficient conditions in order for a tax to be considered ineffective.

C
The tax on gasoline costs a significant amount of money to enforce. Thus, if it does not raise revenue, the tax is ineffective.

This answer is strongly supported. It meets both of our sufficient conditions we are given for a tax to be considered ineffective.

D
The tax on coal burdens all of the people targeted by it, and this tax does not burden anyone who is not targeted by it. Thus, the tax is effective.

This answer is unsupported. There are two sufficient conditions to be met in order for a tax to be considered effective. This answer only satisfies one of the two sufficient conditions.

E
The tax on steel does not cost a significant amount of money to enforce, but it does not raise revenue either. Thus, the tax is ineffective.

This answer is unsupported. This answer fails one of our sufficient conditions for a tax to be considered ineffective. We need both of the sufficient conditions in order for a tax to be considered ineffective.


4 comments

Leadership depends as much on making one’s followers aware of their own importance as it does on conveying a vivid image of a collective goal. Only if they are convinced both that their efforts are necessary for the accomplishment of this goal, and that these efforts, if expended, will actually achieve it, will people follow a leader.

Summary
The stimulus can be diagrammed as follows:

Notable Valid Inferences
If people are following a leader, they are convinced that their efforts are necessary for the accomplishment.
If people are following a leader, they are convinced that their efforts will actually achieve the accomplishment.

A
Some leaders who convince their followers of the necessity of their efforts in achieving a goal fail, nevertheless, to lead them to the attainment of that goal.
This could be true. What matters is that people are convinced that their efforts will achieve the goal, not whether or not the goal is actually achieved.
B
One who succeeds in conveying to one’s followers the relationship between their efforts and the attainment of a collective goal succeeds in leading these people to this goal.
This could be true. (B) tells us that if we succeed in conveying the relationship between people’s efforts and attainment of the goal, then we will succeed in leading them to the goal. Like for (A), nothing in the stimulus contradicts any claims about actually achieving goals.
C
Only if one is a leader must one convince people of the necessity of their efforts for the attainment of a collective goal.
Could be true. (C) says that if you convince people of the necessity of their efforts, then you are a leader. The stimulus gives necessary conditions for when leaders are followed; (C) gives a sufficient condition for being a leader, which isn’t inconsistent with the stimulus.
D
Sometimes people succeed in achieving a collective goal without ever having been convinced that by trying to do so they would succeed.
This could be true. The stimulus gives two necessary conditions for following a leader; the information in (D) that people can succeed without having been convinced that they could succeed is independent of the information in the stimulus.
E
Sometimes people who remain unsure of whether their efforts are needed for the attainment of a collective goal nevertheless follow a leader.
This must be false. As shown below, (E) meets the sufficient condition of “follow leader” but fails the necessary condition of “efforts necessary,” which contradicts the stimulus.

10 comments

Fifty chronic insomniacs participated in a one-month study conducted at an institute for sleep disorders. Half were given a dose of a new drug and the other half were given a placebo every night before going to bed at the institute. Approximately 80 percent of the participants in each group reported significant relief from insomnia during the first two weeks of the study. But in each group, approximately 90 percent of those who had reported relief claimed that their insomnia had returned during the third week of the study.

"Surprising" Phenomenon
Why did approximately 80 percent of people in each of the study’s groups report relief from insomnia during the first two weeks of the study and 90 percent of those from each group who reported relief from insomnia claim their insomnia returned during the third week?

Objective
The right answer will be a hypothesis that explains a key similarity between the 80 percent of people from both the placebo and treatment groups that reported relief from insomnia, the 90 percent of those from each group that reported relief but claimed their insomnia returned, or both.

A
Because it is easy to build up a tolerance to the new drug, most people will no longer experience its effects after taking it every night for two weeks.
This provides a difference between the people in the placebo and treatment groups, but we need a similarity. (A) tells us most people in the treatment group wouldn’t experience the drug’s potential effects after two weeks. This doesn’t explain why the groups had similar results.
B
The psychological comfort afforded by the belief that one has taken a sleep-promoting drug is enough to prevent most episodes of insomnia.
We don’t know if people in either group believed that they’d taken a sleep-promoting drug. Therefore, (B) is irrelevant.
C
The new drug is very similar in chemical composition to another drug, large doses of which have turned out to be less effective than expected.
We don’t know the significance of the chemical composition of the new drug or the size of the dosage taken by people in the treatment group. (C) doesn’t help explain the phenomenon in the stimulus.
D
Most insomniacs sleep better in a new environment, and the new drug has no effect on an insomniac’s ability to sleep.
This points out two key similarities between those in the placebo and treatment groups. Most people in both groups were likely to sleep better in their new environment and the new drug doesn’t affect sleep, helping to explain the similarity in results between the two groups.
E
Some insomniacs cannot reliably determine how much sleep they have had or how well they have slept.
We don’t know if this applies to insomniacs in the study. (E) tells us nothing about why the placebo and treatment groups had similar results.

11 comments

Advertisement: The Country Classic is the only kind of car in its class that offers an antilock braking system that includes TrackAid. An antilock braking system keeps your wheels from locking up during hard braking, and TrackAid keeps your rear wheels from spinning on slippery surfaces. So if you are a safety-conscious person in the market for a car in this class, the Country Classic is the only car for you.

The advertisement says that the Country Classic is the preferable car in its class for safety-conscious consumers. This is because it has an antilock braking system that includes TrackAid. These safety features help when hard braking and driving on slippery sufaces, respectively.

Notable Assumptions
The advertisement says that having TrackAid in addition to an antilock braking system makes Country Classic safer than other cars in its class—by saying this, it implies that other cars lack alternatives to TrackAid that equally increase safety.

A
All of the cars that are in the same class as the Country Classic offer some kind of antilock braking system.
This does not affect the advertisement. The advertisement does not claim that others cars lack an antilock braking system—it claims that other cars lack an antilock braking system that includes TrackAid.
B
Most kinds of cars that are in the same class as the Country Classic are manufactured by the same company that manufactures the Country Classic.
This does not affect the advertisement. The same company can manufacture cars with different features and systems.
C
Without an antilock braking system, the wheels of the Country Classic and other cars in its class are more likely to lock up during hard braking than they are to spin on slippery surfaces.
This does not affect the advertisement. It discusses cars that lack an antilock braking system, whereas we know that the Country Classic does have this feature, which is part of what purportedly makes it safer than other cars.
D
Other cars in the same class as the Country Classic offer an antilock braking system that uses a method other than TrackAid to prevent rear wheels from spinning on slippery surfaces.
This weakens the advertisement. It attacks its assumption that TrackAid is the only way to prevent rear wheels from spinning on slippery surfaces: if other cars have an equally safe alternative method of prevention, they could be just as safe as the Country Classic.
E
The Country Classic is more expensive than any other car in its class.
This does not affect the advertisement, which discusses safety, not price.

6 comments