Summary
Engine noise from boats traveling through killer whales’ habitats ranges from a frequency that overlaps with the acoustical range in which the whales communicate with each other. Although the whales do not act differently when the engine noise is present, the noise can be loud enough to cause hearing damage over time. Therefore… (the correct answer will be the conclusion).
Strongly Supported Conclusions
The engine noise could impact how killer whales communicate with each other after enough time.
A
younger killer whales are better able to tolerate engine noise from boats than older whales are
This is not supported by the stimulus and requires some unreasonable assumptions to make it work. You must assume that younger killer whales have been exposed to engine noise for a shorter period of time than older ones.
B
killer whales are less likely to attempt to communicate with one another when boat engines are operating nearby
The stimulus does say anything about what killer whales prefer.
C
noise from boat engines may impair killer whales’ ability to communicate
The stimulus says that engine noise *can* damage hearing loss over time. Killer whales communicate through screams and squeals. So, it is easy to support that boat engines could eventually impair the whales’ ability to communicate.
D
killer whales are most likely to prefer areas where boat traffic is present, but light
There is no support anywhere in the stimulus about what killer whales “prefer.”
E
killer whales would probably be more successful in finding food if boats did not travel through their habitats
You have to assume that killer whales communicate to find food. There is no evidence in the stimulus that supports this assumption.
Summarize Argument
The author concludes that Bruch Industries isn’t a member of the trade group. This is based on the fact that every company listed in a particular document belongs to the trade group, and Bruch Industries isn’t listed in that document.
Identify and Describe Flaw
The author confuses a sufficient condition for being in the trade group with a necessary condition. Being on the list is sufficient to know that a company is in the trade group, because every company listed is a member of the trade group. But that doesn’t mean being on the list is required to be a member. It’s possible for a company to be a member even if it’s not on the list. In other words, “Every company on the list is in the group” does not imply “every company in the group is on the list.”
A
gives no reason to think that Bruch Industries would want to belong to the trade group
Bruch’s desires are irrelevant to the argument. The argument concerns whether the company is a member of the trade group, not whether it wants to be.
B
does not present any evidence that the document names every member of the trade group
The author fails to show that the document lists all of the members of the group. That’s why not being listed in the document doesn’t imply lack of membership in the group.
C
does not explain how it is that the trade group could have inadvertently sent out a secret document
It doesn’t matter how the author got the secret document. We know the document exists and the trade group confirmed that everyone on the list is a member of the group.
D
presents no reason why Bruch Industries would not want its membership in the trade group to be known
Brush’s desires are irrelevant to the argument. The argument concerns whether Brush is a member of the group, not whether it would want its membership to be known.
E
takes for granted the accuracy of a statement by a representative who had a reason to withhold information
The representative confirmed that every company listed in the document is a member of the group. The reasoning isn’t flawed because the author accepts the representative’s confirmation. We have no reason to think this confirmation is inaccurate.
Yoko: Children’s stories still tend to have clearly immoral characters in them, but now these characters tend not to be the sort that frighten children. Surely that’s an improvement.
Speaker 1 Summary
Peter argues that children’s stories should include clearly immoral characters (which they usually did in the past, but now do not). Why? Because it’s important to teach children the consequences of being bad.
Speaker 2 Summary
Yoko doesn’t make an argument, but does make several factual claims. First, modern children’s stories usually do have clearly immoral characters. Second, these characters are less frightening than in the past. And finally, it’s a good thing to avoid frightening children.
Objective
We’re looking for a disagreement between Peter and Yoko. The two disagree about whether modern children’s stories usually contain clearly immoral characters.
A
should be less frightening than they are
Neither speaker makes this claim. Yoko is the only one to talk about stories being frightening, but never says that stories should be less frightening than they currently are.
B
tend to be less frightening than earlier children’s stories were
Yoko agrees with this, but Peter doesn’t express an opinion. Peter doesn’t talk about children’s stories being frightening at all, either now or in the past.
C
differ significantly in overall quality from earlier children’s stories
Neither speaker talks about the overall quality of children’s stories, currently or in earlier times, let alone to compare the two.
D
tend to have clearly immoral characters in them
Peter disagrees with this but Yoko agrees, so this is the speakers’ disagreement. Peter states that modern stories, unlike earlier ones, don’t usually have clearly immoral characters. Yoko, however, says that modern stories usually do have clearly immoral characters.
E
should help children learn the consequences of being bad
Peter agrees with this, but Yoko doesn’t express an opinion. Yoko never discusses what kinds of lessons children’s stories should impart on their readers.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that an overabundance of algae is harmful to smaller fish in this pond. This is based on the fact that over the past 15 years, the few times that the author has seen a lot of dead small fish has coincided with the times that he has noticed unusually large amounts of algae in the water.
Identify and Describe Flaw
The author assumes that the correlation between lots of dead small fish and lots of algae is explained by algae causing harm to the small fish. This overlooks alternate explanations for the correlation. Perhaps there’s a third factor that causes both the algae and the dead fish. The author also assumes that his own observations of the timing of dead small fish and lots of algae is representative of the general pattern of dead small fish and lots of algae in the pond.
A
presumes, without providing justification, that smaller fish are somehow more susceptible to harm as a result of overabundant algae than are larger fish
The author never compares the effects of algae to the effects of larger fish.
B
fails to consider that the effects on smaller fish of overabundant algae may be less severe in larger bodies of water with more diverse ecosystems
The author’s conclusion doesn’t concern other bodies of water besides “this pond.”
C
ignores the possibility that the same cause might have different effects on fish of different sizes
The author’s conclusion only concerns the effects of algae on “smaller fish.” Fish of other sizes are not relevant to the argument.
D
ignores the possibility that the overabundance of algae and the deaths of smaller fish are independent effects of a common cause
This possibility presents an alternate explanation for the author’s evidence. Perhaps algae isn’t harmful to smaller fish, but rather the algae and deads of small fish are both results of some other cause.
E
ignores the possibility that below-normal amounts of algae are detrimental to the pond’s smaller fish
The author didn’t say that below-normal amounts of algae are not harmful to smaller fish. The conclusion is that overabundance of algae is harmful, but this doesn’t imply that the author thinks less than abundant algae isn’t harmful.
Saldana: Political debates almost always benefit the candidate who has the better debating skills. Thus, they don’t really help voters determine which candidate is most qualified for office.
Speaker 1 Summary
The public should demand political debates before elections. Why? Because by watching a debate, voters are better able to choose which candidate is best suited for office.
Speaker 2 Summary
Political debates don’t help voters determine which candidate is best suited for office. Why? Because debates benefit the candidate who has the better debating skills.
Objective
We need a statement that Tanner and Saldana disagree on. Tanner thinks that debates help voters determine which candidate is best suited for office. Saldana thinks that debates don’t really help voters make this determination.
A
Political candidates with strong debating skills are more likely to win elections than those with weak debating skills.
Tanner does not express an opinion on this statement. We only know that Tanner believes political debates help voters make their decisions.
B
A voter who watches a political debate will likely be better able, as a result, to determine which candidate is more qualified for office.
Tanner and Saldana disagree on this statement. Tanner agrees and that’s why he thinks there should be political debates before every election. Saldana disagrees because she thinks debates only reflect a candidate’s debating skills, not whether they are best suited for office.
C
Debating skills are of little use to politicians in doing their jobs once they are elected to office.
Tanner does not express an opinion on this statement. Tanner may think that debating skills help voters determine a candidate’s suitability, but he does not express whether these skills are useful or not after candidates are elected.
D
The candidates with the best debating skills are the ones who are most qualified for the political offices for which they are running.
Tanner does not express an opinion on this statement. We only know that Tanner thinks that debates are informative for voters. We don’t know whether Tanner thinks the debating skills specifically are indicative of a candidate’s suitability.
E
Political debates tend to have a major effect on which candidate among those participating in a debate will win the election.
Tanner does not express an opinion on this statement. We don’t know whether Tanner thinks that debates causally effect a candidate’s chances of winning an election.
"Surprising" Phenomenon
Why do the busiest highways have the fewest fatal accidents?
Objective
Any hypothesis explaining this phenomenon must rely on a difference between the highways carrying the most traffic and other highways. This difference must explain why fatal accidents are less likely on the busiest highways than on other types of highways.
A
Drivers have more accidents when they become distracted.
It is not implied whether drivers on the busiest highways are more or less likely to become distracted than drivers on other highways, so this is useless without more information.
B
The highways that have the highest rate of fatal accidents have moderate volumes of traffic.
This adds more detail to the phenomenon without explaining it. It does not address the busiest highways, or explain why they have fewer fatal accidents than other types of highways.
C
Most of the motorists on very heavily traveled highways tend to be commuting to or from work.
It is not implied whether commuters are more or less likely than other drivers to be in a fatal accident, so this is useless without more information.
D
Most serious accidents occur when vehicles are moving at a high rate of speed.
This explains why the busiest highways have the lowest rate of fatal traffic accidents. Because of their congestion, these highways are less likely to carry fast-moving vehicles, and so are less likely to be the site of fatal accidents.
E
Heavily traveled highways do not always carry a higher proportion of large trucks.
This does not imply that the busiest highways carry fewer trucks than other highways. It allows for the possibility that they often or usually carry a higher proportion of large trucks than other highways.
Summarize Argument
The author concludes that certain lawmakers think that theft and bribery are equally harmful. She supports this by saying that they mandate identical penalties for both.
Notable Assumptions
The author assumes that the lawmakers set penalties based on how harmful they believe a crime is. In other words, she assumes that a crime’s penalty accurately reflects the harm that the lawmakers think it causes.
A
In general, lawmakers mandate penalties for crimes that are proportional to the harm they believe to result from those crimes.
If lawmakers generally mandate penalties that correspond to the harm that they think results from a crime, then it’s likely the lawmakers in these jurisdictions consider theft and bribery equally harmful, since the penalties for both are the same.
B
In most cases, lawmakers assess the level of harm resulting from an act in determining whether to make that act illegal.
The argument addresses how lawmakers set penalties for crimes, not how they decide if an act is illegal. Instead of (B), we need to know whether lawmakers assess the level of harm resulting from an act in determining the penalty for that act.
C
Often, in response to the unusually great harm resulting from a particular instance of a crime, lawmakers will mandate an increased penalty for that crime.
This suggests that a very harmful case of theft or bribery would lead lawmakers to increase the penalty. But the author is focusing on the harm of theft and bribery overall, not just extreme cases.
D
In most cases, a victim of theft is harmed no more than a victim of bribery is harmed.
The author only discusses how much harm lawmakers think bribery and theft cause; it doesn’t matter how much they actually cause. Even if they cause equal harm, this doesn’t help to determine whether lawmakers mandate penalties based on how much harm they think a crime causes.
E
If lawmakers mandate penalties for crimes that are proportional to the harm resulting from those crimes, crime in those lawmakers’ jurisdictions will be effectively deterred.
The author doesn’t mention anything about crime being effectively deterred. Instead, we need to know whether lawmakers actually “mandate penalties for crimes that are proportional to the harm resulting from those crimes” in the first place.
Summarize Argument
The author concludes that people are wrong to say that we should learn the lessons of history. This is because the lessons are difficult to discern, and it’s not certain they could ever be applied even if we discovered them.
Identify Argument Part
The referenced text is the position that the author’s argument is disputing. Even trying to learn the lessons of history, the author argues, is ultimately a waste of time.
A
It sets out a problem the argument as a whole is designed to resolve.
The argument isn’t trying to resolve a problem. It’s disputing the view—that we should learn the lessons of history—expressed in the referenced text.
B
It is compatible with accepting the argument’s conclusion and with denying it.
The author concludes that discovering the lessons of history is a fruitless task. The referenced text meanwhile states that we should try to discover them, which contradicts the conclusion.
C
It is a position that the argument simply takes for granted is false.
The author doesn’t take for granted that we shouldn’t learn the lessons of history. Instead, she argues it’s a pointless endeavor to undertake.
D
It expresses the position the argument as a whole is directed toward discrediting.
The referenced text says that we should learn the lessons of history. The author says we shouldn’t, since the lessons of history are difficult to discover and of little practical value. Thus, the author attempts to discredit the position expressed in the referenced text.
E
It is an assumption that is required in order to establish the argument’s conclusion.
The author doesn’t assume that we should learn the lessons of history. Instead, she argues against this position.
Summarize Argument
Sigerson proposed an ethical guideline that prevents politicians from accepting campaign contributions from companies that do business with the city. The author concludes that this proposal is dishonest. This is based on the fact that Sigerson has taken contributions from such companies throughout his career in city politics.
Identify and Describe Flaw
The fact that Sigerson accepted contributions in the past doesn’t indicate that he believes his proposal shouldn’t apply to him or that his past acceptance of contributions is ethically acceptable. So there’s no basis to call the proposal “dishonest.” Sigerson may have taken advantage of the lack of a rule against accepting such contributions and now wants to ban those contributions for everyone going forward.
A
confuses a sufficient condition for adopting ethical guidelines for politicians with a necessary condition for adopting such guidelines
The argument isn’t based on conditional logic, so there’s no confusion of sufficient and necessary conditions.
B
rejects a proposal on the grounds that an inadequate argument has been given for it
The author doesn’t reject the proposal; she simply calls it dishonest. Also, the basis of the conclusion isn’t that there’s been an inadequate argument for the proposal. The basis is Sigerson’s past acceptance of contributions.
C
fails to adequately address the possibility that other city politicians would resist Sigerson’s proposal
Whether other politicians would resist the proposal is irrelevant, because the argument doesn’t concern the likelihood that the proposal will pass.
D
rejects a proposal on the grounds that the person offering it is unfamiliar with the issues it raises
The basis of the author’s conclusion isn’t that Sigerson is unfamiliar with the issues raised in the proposal. The basis is Sigerson’s own acceptance of contributions in the past.
E
overlooks the fact that Sigerson’s proposal would apply only to the future conduct of city politicians
In calling Sigerson’s proposal dishonest, the author seems to think that Sigerson’s past conduct is relevant. But Sigerson isn’t trying to cheat the rules; Sigerson has to follow the new guidelines, too, if the proposal is passed. So there’s no dishonesty in the proposal.