A hardware store generally sells roughly equal numbers of Maxlast brand hammers and Styron brand hammers. Last week, all of the Maxlast hammers were put on sale and placed in a display case just inside the store entrance while the Styron hammers retained their usual price and location. Surprisingly, the Styron hammers slightly outsold the Maxlast hammers.

"Surprising" Phenomenon
Why did Styron hammers outsell Maxlast hammers at the hardware store last week, even though both brands usually sell equally, and Maxlast hammers were on sale and displayed at the store entrance last week, while Styron hammers stayed at their regular spot and price?

Objective
The correct answer will be a hypothesis that explains a key difference in customers’ interest in the hammer brands before and after last week’s changes. It must either result in customers being more likely to buy Styron hammers, or less likely to buy Maxlast hammers.

A
For the first several seconds after shoppers enter a store, they do not take detailed notice of the store’s merchandise.
This explains the shift in customer interest in the hammer brands after last week's changes. Since customers don’t pay close attention in the first few seconds after entering a store, they were less likely to notice the Maxlast hammers displayed at the entrance.
B
Most of the hardware store’s customers are attracted by quality and service rather than low prices.
Just because customers prefer quality over low prices doesn’t mean they see lower-priced items as lower quality. Also, we don’t know which hammer brand is higher quality, or if they’re the same quality. So, we still can’t explain why Styron hammers outsold Maxlast last week.
C
Customers who bought the Maxlast hammers last week commonly mentioned the sale as their reason for buying a hammer at that time.
This makes the sale results even more surprising. If some customers bought Maxlast hammers because of the sale, why didn’t more customers do the same? We still don’t know why Styron hammers outsold Maxlast hammers during the week of the Maxlast sale.
D
The hardware store circulated flyers that publicized the sale prices on Maxlast hammers.
Again, this makes the sale results even more surprising. If the hardware store advertised the Maxlast sale, why did Styron hammers still outsell Maxlast hammers?
E
In general, a single item that is on sale will not motivate shoppers to make a special trip to a store.
Even if shoppers didn’t make a special trip to the hardware store to buy the discounted Maxlast hammers, it’s still surprising that Styron outsold Maxlast, especially because both brands usually sell equally.

35 comments

The Asian elephant walks with at least two, and sometimes three, feet on the ground at all times. Even though it can accelerate, it does so merely by taking quicker and longer steps. So the Asian elephant does not actually run.

Summary
The author concludes that the Asian elephant does not run. Why? Because the Asian elephant always has at least two feet on the ground at all times. In addition, it accelerates only by taking quick and longer steps.

Missing Connection
We’re trying to prove that the Asian elephant doesn’t run. But do we know from the premises what “running” requires? No. We don’t know what can establish that something doesn’t run. So, at a minimum, the correct answer should tell us what’s required to run.
To go further, we can anticipate some specific relationships that would make the argument valid. Any answer that gets us from one of the premises to “not run” could be correct. For example:
In order to run, something must have fewer than two feet on the ground at some point in time.
In order to run, something must accelerate in a way besides merely taking quicker and longer steps.

A
If an animal cannot accelerate, then it cannot run.
But the Asian elephant can accelerate. So (A) doesn’t establish that the elephant can’t run.
B
To run, an animal must have all of its feet off the ground at once.
(B) establishes that running requires having all feet off the ground at once. But we know the Asian elephant doesn’t have all of its feet off the ground at once — it always has at least 2 feet on the ground. So (B) allows us to conclude that the Asian elephant doesn’t run.
C
The Asian elephant can walk as quickly as some animals run.
(C) doesn’t tell us what’s required to run. So it doesn’t establish that the Asian elephant can’t run.
D
It is unusual for a four-legged animal to keep three feet on the ground while walking.
(D) doesn’t tell us what’s required to run. So it doesn’t establish that the Asian elephant can’t run.
E
All four-legged animals walk with at least two feet on the ground at all times.
(E) doesn’t tell us what’s required to run. So it doesn’t establish that the Asian elephant can’t run.

7 comments

Two lakes in the Pawpaw mountains, Quapaw and Highwater, were suffering from serious declines in their fish populations ten years ago. Since that time, there has been a moratorium on fishing at Quapaw Lake, and the fish population there has recovered. At Highwater Lake, no such moratorium has been imposed, and the fish population has continued to decline. Thus, the ban on fishing is probably responsible for the rebound in the fish population at Quapaw Lake.

Summarize Argument
The author concludes that the ban on fishing caused the fish population at Quapaw Lake to rebound. His evidence is that the fish population at Quapaw Lake rebounded after a fishing ban was put in place. On the other hand, the fish population at Highwater Lake, where there was no fishing ban, didn’t rebound.

Notable Assumptions
In order for the fishing ban to have made a difference at Quapaw Lake, the author must assume there was a substantial amount of fishing at Quapaw Lake before the ban went into effect. The author must also assume that no unaccounted-for outside factor (e.g. climate conditions, introduction of new species into the lake) caused the rebound.

A
Highwater Lake is in an area of the mountains that is highly susceptible to acid rain.
This provides an alternate explanation as to why the fish population at Highwater Lake continued to decline. However, for this to weaken the author’s conclusion we would need to know if Quapaw Lake isn’t located in an area highly susceptible to acid rain.
B
Prior to the ban, there was practically no fishing at Quapaw Lake.
The fishing ban couldn’t have caused the fish population to rebound at Quapaw Lake. There was hardly any fishing to begin with.
C
Highwater Lake is much larger than Quapaw Lake.
We don’t care how big the lakes are. We care about their fish populations and how fishing bans effect them.
D
Several other lakes in the Pawpaw mountains have recently had increases in their fish populations.
Perhaps those lakes also had fishing bans put in place.
E
There used to be a greater variety of fish species in Highwater Lake than in Quapaw Lake, but there no longer is.
We don’t care about variety. We care about the total population.

24 comments

Merton: A study showed that people who live on very busy streets have higher rates of heart disease than average. I conclude that this elevated rate of heart disease is caused by air pollution from automobile exhaust.

Ortiz: Are you sure? Do we know whether people living on busy streets have other lifestyle factors that are especially conducive to heart disease?

Summarize Argument: Phenomenon-Hypothesis
Merton points out that a study shows a correlation between living on very busy streets and heart disease. Merton hypothesizes that the higher heart disease rate of people on these streets is caused by air pollution from cars.
Ortiz responds that there might be other factors that are the cause of the higher heart disease rate among people who live on busy streets.

Describe Method of Reasoning
Ortiz responds by pointing out that there might be other explanations for the correlation observed in the study described by Merton. Merton’s explanation is that air pollution caused by cars is causing heart disease. Ortiz suggests that the real explanation might be related to other lifestyle factors.

A
raising a question about the validity of the study that Merton cites
Ortiz doesn’t question the validity of the study. He doesn’t question the truth of the correlation found in the study. What he questions is Merton’s explanation for that correlation. Merton’s explanation is not part of the study.
B
contending that Merton needs to take into account other effects of air pollution
Ortiz doesn’t point out the need to consider other effects of air pollution. He points out the need to consider other causes of heart disease.
C
claiming that Merton misunderstands a crucial aspect of the study’s findings
Ortiz doesn’t claim Merton misunderstands anything about the study’s findings. Ortiz might agree that Merton perfectly understands the results of the study. What Ortiz questions is Merton’s explanation of those results. Merton’s explanation isn’t part of the study’s findings.
D
raising a counterexample to the general conclusion that Merton draws
Ortiz doesn’t raise a counterexample. A counterexample would involve the existence of people who live on a busy street, but whose heart disease is not caused by air pollution. Ortiz doesn’t point out that this kind of person exists.
E
suggesting that alternative explanations for the study’s findings need to be ruled out
Ortiz, through rhetorical questions, suggests that the cause of heart disease for people on busy streets might be other lifestyle factors. To conclude that air pollution is the cause, we’d need to rule out these other explanations.

4 comments

Economist: Owing to global economic forces since 1945, our country’s economy is increasingly a service economy, in which manufacturing employs an ever smaller fraction of the workforce. Hence, we have engaged in less and less international trade.

"Surprising" Phenomenon

Why does shifting to a service-based economy with fewer manufacturing jobs lead the economist's country to engage in less international trade?

Objective

The correct answer will be a hypothesis that explains a key difference between service and manufacturing economies. This difference must either explain why service-based economies are less engaged in international trade or why manufacturing-based economies are more engaged in international trade.

A
International trade agreements have usually covered both trade in manufactured goods and trade in services.

This gives us a similarity between trade in manufactured goods and trade in services rather than a difference. Trade agreements may cover both kinds of trade, but we still don’t know why an increasingly service-based economy leads to a decrease in international trade engagement.

B
Employment in the service sector tends to require as many specialized skills as does employment in manufacturing.

(B) gives a similarity between service employment and manufacturing employment. It doesn’t connect either to international trade or provide an explanation for why increased service employment and decreased manufacturing employment lead to decreased international trade engagement.

C
Because services are usually delivered in person, markets for services tend to be local.

This provides a difference in the market for services as opposed to manufactured goods. Because services are delivered in person, markets for services are local. Thus, if an economy is increasingly service-based, it will engage in less international trade.

D
Many manufacturing jobs have been rendered obsolete by advances in factory automation.

This may explain why the country is becoming more service-based, but it doesn’t explain why a service-based economy is less engaged in international trade. We need an answer that links the shift from manufacturing to services with a drop in international trade.

E
Some services can be procured less expensively from providers in other countries than from providers in the economist’s country.

We need an answer that explains why more services in the economist's country lead to less international trade. (E) only says that some services are cheaper abroad but doesn’t connect this to the economist’s country's level of international trade.


15 comments

Biologist: A careful study of the behavior of six individual chameleons concluded that lizards such as chameleons bask in the sun not only for warmth but also to regulate their production of vitamin D. Critics of the study—although correct in observing that its sample size was very small—are wrong to doubt its results. After all, the study’s author is well regarded professionally and has been doing excellent work for years.

Summarize Argument
The author concludes that critics of a study involving chameleons are wrong to doubt the study’s conclusion. This is based on the fact that the study’s author is well-regarded professionally and has been doing excellent work for years.

Identify and Describe Flaw
The professional reputation and background of the study’s author doesn’t constitute a reason to trust the study’s conclusion. What matters is how the study was conducted and whether the study’s conclusion is reasonable.

A
takes the behavior of chameleons to be generalizable to lizards as a whole
The author’s reasoning isn’t based on generalizing from chamelons to lizards as a whole. The reasoning is based on the study author’s background and whether that shows the results are reliable.
B
fails to explain how chameleons regulate their vitamin D production by basking in the sun
The author didn’t need to explain how chameleons regulate their vitamin D. This issue doesn’t affect whether the study author’s background constitutes a reason to find the conclusion reliable.
C
focuses its attention on the study’s author rather than on the study itself
The author focuses on the study author’s professional reputation and background rather than on the study itself. This is a flaw, because the author’s reputation and background do not reveal anything about the reliability of the study and its conclusion.
D
fails to demonstrate that the study’s critics have relevant expertise
The argument doesn’t rely on the study’s critics for support, so their expertise is irrelevant.
E
holds the study’s author to a higher standard than it holds the study’s critics
The argument doesn’t concern different standards for different people. The author simply believes that the reputation/background of the study’s author constitutes a reason to trust the study’s conclusion.

5 comments

Doris: I’ve noticed that everyone involved in student government is outspoken. So if we want students to be more outspoken, we should encourage them to become involved in student government.

Zack: Those who are in student government became involved precisely because they are outspoken in the first place. Encouraging others to become involved will do nothing to make them more outspoken.

Speaker 1 Summary
Doris concludes that if we want students to be more outspoken, we should encourage them to become involved in student government. This is based on her observation that everyone involved in student government is outspoken. Doris’s argument assumes a causal relationship between involvement in student government and being outspoken.

Speaker 2 Summary
Zack concludes that encouraging people to get involved in student government won’t make them more outspoken. This is because being outspoken is the cause of involvement in student government.

Objective
We’ re looking for a point of disagreement. The speakers disagree about the direction of the causal relationship between involvement in student government and being outspoken. Doris thinks involvement causes being outspoken. Zack thinks the relationship is reversed.

A
students should be more outspoken
Neither speaker expresses an opinion. Doris doesn’t say we want students to be outspoken, only what we should do if we want them to be more outspoken. Zack doesn’t say anything should or should not happen.
B
students should be encouraged to become involved in student government
Neither speaker expresses an opinion. Doris only says we should encourage student government involvement if we want students to be more outspoken. That’s not the same as wanting students to be more involved in student government. Zack doesn’t say what should or should not happen.
C
becoming involved in student government makes students more outspoken
This is a point of disagreement. Doris thinks involvement in student government makes students more outspoken. Zack doesn’t think so.
D
all students who are involved in student government are outspoken
This is not a point of disagreement. Although Doris agrees with this, Zack also could agree. He doesn’t say that there are any students involved in student government who are not outspoken.
E
students will not become more outspoken unless they become involved in student government
Neither speaker expresses an opinion. Doris thinks involvement causes becoming more outspoken. But she doesn’t suggest that involvement is required. Zack also does not suggest that involvement is required to be outspoken.

5 comments

Government official: Residents who are foreign citizens can serve as public servants at most levels, but not as cabinet secretaries. This is wise, since cabinet secretaries perform some duties that should be performed only by citizens, and no one should be appointed to a position if it involves duties that person should not perform. Moreover, a cabinet undersecretary is expected to serve as cabinet secretary when the actual secretary is unavailable. So, _______.

Summary

The stimulus sets forth several rules.

Foreign citizens cannot serve as cabinet secretaries. This is justified because cabinet secretaries need to do things that only domestic citizens can do (and foreign citizens can’t do).

No one should be appointed to a position that involves duties a person can’t perform.

In addition, a cabinet undersecretary is expected to serve as cabinet secretary when the actual cabinet secretary is unavailable.

Strongly Supported Conclusions

Since cabinet undersecretaries are expected to serve as cabinet secretaries at some times, and foreign citizens can’t serve as cabinet secretaries, this strongly suggests foreign citizens shouldn’t serve as cabinet undersecretaries.

A
foreign citizens who serve as public servants should be granted citizenship in the country they serve

Unsupported. Nothing in the stimulus concerns conditions for granting citizenship. We know that non-citizens shouldn’t serve in certain positions. That doesn’t imply we should ever make them citizens.

B
foreign citizens should not be appointed as cabinet undersecretaries

Strongly supported. Foreign citizens can’t serve as cabinet secretaries, so they shouldn’t serve as undersecretaries, who would be expected to occasionally step in as cabinet secretaries. No one should be appointed to a position whose duties they can’t fulfill.

C
only former cabinet undersecretaries should be appointed as cabinet secretaries

Unsupported. We know foreign citizens shouldn’t be cabinet secretaries. But nothing excludes non-former-undersecretaries from serving as cabinet secretaries.

D
foreign citizens should be eligible to serve as cabinet secretaries

Unsupported. The author doesn’t provide reasons to change the current restrictions on service. The stimulus simply describes the rules, and we are supposed to apply them. Not advocate for a change.

E
cabinet undersecretaries should not be expected to stand in for cabinet secretaries

Unsupported. We’re not given reasons that undersecretaries shouldn’t step in for the secretaries. We’re given reasons a foreign citizen should not serve as an undersecretary or secretary. The stimulus doesn’t give us enough to infer that rules should be changed.


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