Summarize Argument: Phenomenon-Hypothesis
The author concludes that there’s no need to look further for an explanation of the difference between the results the university study arrived at and the results the governmental study arrived at because each study used a different method of investigation.
Identify and Describe Flaw
The author reasons that since the university study and governmental study used different methods of investigation, there’s no need to look for another explanation of the studies arriving at different results. However, the argument is flawed because the author fails to consider that two studies using different methods of investigation doesn’t guarantee that they’ll arrive at different results. Different investigation methods can arrive at the same result.
A
distinguish between a study produced for the purposes of the operation of government and a study produced as part of university research
We don’t know that the governmental study was produced for the purpose of the operation of government. The government could’ve produced it for a different reason.
B
distinguish between a method of investigation and the purpose of an investigation
The author only discusses the method of investigation for each study. The author doesn’t discuss purpose.
C
recognize that only one of the studies has been properly conducted
We have no idea if either of the studies have or haven’t been properly conducted.
D
recognize that two different methods of investigation can yield identical results
The argument commits this flaw. The author argues that the studies arriving at different results is explained by them using different methods of investigation, without recognizing that the studies could’ve arrived at the same results with different methods of investigation.
E
recognize that varying economic conditions result in the average workweek changing in length
The argument isn’t concerned with economic conditions. The author only argues that the studies arriving at different results is explained by them using different methods of investigation.
Summary
The author concludes that differences in camera lens resolution are irrelevant for practical photography. Why? Because all modern lenses project far more detail onto film than any photographic film can reproduce in a developed image.
Notable Assumptions
What if differences in resolution could be important to some aspect of practical photography besides the amount of detail projected onto film? The author assumes that there’s no other way in which differences in resolution could be relevant to practical photography.
This isn’t a question where I’d go in with a specific prediction about what the author assumes. Let’s keep an open mind.
This isn’t a question where I’d go in with a specific prediction about what the author assumes. Let’s keep an open mind.
A
The definition of the term “resolution” does not capture an important determinant of the quality of photographic instruments and materials.
The author could very well agree that “resolution” captures something important about the quality of photographic instruments and materials, such as camera lens and film. The point, however, is that the differences in resolution of camera lens aren’t practically relevant. “Resolution” is still an important feature, but the differences in camera lens resolution don’t have to be.
B
In determining the amount of detail reproduced in the developed photographic image, differences in the resolutions of available lenses do not compound the deficiencies of available film.
(B) is necessary because if it were not true — if differences in lens resolution DO compound (in other words, make worse) the deficiencies of film, then this is a reason lens resolution might make a practical difference. So the author must assume that differences in lens resolution do NOT make worse the deficiencies of film in order to conclude that there’s no practical difference between different lens resolutions.
C
Variations in the method used to process the film do not have any significant effect on the film’s resolution.
(C) doesn’t say anything about camera lens resolution. The author doesn’t have to assume anything about film resolution except as it relates to camera lens resolution. If variations in processing film do have large effects on film’s resolution, that doesn’t undermine the author’s point, which is that camera lens project more detail than any film can capture in an image, and that this is why lens resolution differences don’t matter.
D
Flawless photographic technique is needed to achieve the maximum image resolution possible with the materials and equipment being used.
The author asserts that modern lenses project far more detail onto film than any film can reproduce. But there’s no indication the author believes we “need” to use “flawless” technique achieve this level of detail or any other level of detail.
E
The only factors important in determining the degree of detail reproduced in the final photographic print are the resolution of the camera’s lens and the resolution of the film.
(E) isn’t necessary, because even if there are other factors important to the level of detail in the final print (such as the quality of a printer, perhaps), the author’s reasoning involves only the relationship between lens resolution and the detail reproducible on a developed image. After we get the image, there might be further factors that affect the detail of a printed image, but the author’s argument doesn’t relate to this stage.
Summarize Argument: Phenomenon-Hypothesis
The conservationists hypothesize that non-native predators are endangering ringtail opossums, instead of a food scarcity. Why? Because non-native foxes killed 75 percent of a particular group of opossums that had been rehabilitated and returned to the wild.
Notable Assumptions
The conservationists assume the group of opossums raised in captivity died in a way typical of the general ringtail opossum population. This means assuming the group was large enough and diverse enough to be representative of ringtail opossums in Australia. They also assume a food scarcity would not make ringtail opossums any more vulnerable to predators and that their endangerment cannot be explained by anything except non-native predation.
A
There are fewer non-native predator species that prey on the ringtail opossum than there are native species that prey on the ringtail opossum.
This doesn’t mean non-native predators pose a larger threat. If anything, it suggests the total number of opossums killed by native predators could be greater than the number killed by non-native predators, which would weaken the argument.
B
Foxes, which were introduced into Australia over 200 years ago, adapted to the Australian climate less successfully than did some other foreign species.
This is irrelevant. It doesn’t mean other non-native species pose an even larger threat to ringtail opossums than foxes—there’s no indication those other species even prey on foxes.
C
The ringtail opossums that were raised in captivity were fed a diet similar to that which ringtail opossums typically eat in the wild.
This suggests the opossums killed had diets that were typical of wild opossums, not that their cause of death was typical. It doesn’t disfavor the leading alternative hypothesis, a food scarcity, because it doesn’t imply the opossums killed were able to find food in the wild.
D
Few of the species that compete with the ringtail opossum for food sources are native to Australia.
This is irrelevant. The conservationists explicitly blame non-native predators for the ringtail opossum’s endangerment, not species that compete with them for food.
E
Ringtail opossums that grow to adulthood in the wild defend themselves against foxes no more successfully than do ringtail opossums raised in captivity.
This rules out an alternative explanation for the opossums’ deaths: that the opossums raised in captivity were killed by foxes in large numbers because they were unusually bad at protecting themselves.
Summary
If monster is horrific, it’s threatening.
If monster is physically dangerous, it’s threatening.
If monster inspires revulsion, it’s horrific.
If monster is physically dangerous, it’s threatening.
If monster inspires revulsion, it’s horrific.
Notable Valid Inferences
If a monster inspires revulsion, then it’s threatening.
A
Any horror-story monster that is threatening is also horrific.
Could be false. We know that all monsters that are horrific are threatening. This doesn’t mean every monster that’s threatening is horrific. There can be threatening monsters that aren’t horrific (maybe they’re threatening for some other reason).
B
A monster that is psychologically dangerous, but that does not inspire revulsion, is not horrific.
Could be false. We know that monsters that inspire revulsion are horrific. That doesn’t imply monsters that don’t inspire revulsion are not horrific. They can still be horrific for other reasons besides revulsion.
C
If a monster triggers infantile fears but is not physically dangerous, then it is not horrific.
Could be false. We know that physically dangerous monsters are threatening. We also know that horrific monsters are threatening. This doesn’t imply that monsters that aren’t physically dangerous aren’t horrific. A monster can be horrific without being physically dangerous.
D
If a monster is both horrific and psychologically threatening, then it does not inspire revulsion.
Could be false. We know that monsters that inspire revulsion are horrific. This doesn’t imply that monsters that are horrific don’t inspire revulsion. It’s possible every monster that’s horrific and threatening inspires revulsion.
E
All monsters that are not physically dangerous, but that are psychologically dangerous and inspire revulsion, are threatening.
Must be true. The stimulus tells us that all monsters that inspire revulsion are horrific, and all monsters that are horrific are threatening. So, all monsters that inspire revulsion are threatening.
Summarize Argument
The researcher concludes the study does not support recommending North Americans eat fewer calories to extend their lives. Why not? Because unnaturally calorific laboratory diets are the reason a reduced-calorie diet increased longevity in the study.
Notable Assumptions
The researcher assumes that North Americans’ diets are more in line with their natural calorie intake than the diets of laboratory animals. Furthermore, she assumes the animals studied had a pre-diet calorie intake typical for laboratory animals.
A
North Americans, on average, consume a higher number of calories than the optimal number of calories for a human diet.
This challenges the assumption that the laboratory animals’ unnaturally high calorie intake makes them dissimilar from North Americans. If North Americans consume more calories than optimal, then they are similar to laboratory animals in that way, not different.
B
North Americans with high-fat, low-calorie diets generally have a shorter life expectancy than North Americans with low-fat, low-calorie diets.
This relationship between fat intake and life expectancy does not imply that the study’s findings can be correctly extended to North Americans. The researcher does not say fat intake was examined separately from calorie intake.
C
Not all scientific results that have important implications for human health are based on studies of laboratory animals.
This states that some studies with implications for human health do not involve laboratory animals, not that studies of laboratory animals must or usually have implications for human health.
D
Some North Americans who follow reduced-calorie diets are long-lived.
This does not say North Americans who eat fewer calories are tend to live longer—it’s possible North Americans on normal diets are more likely to be long-lived than those on reduced-calorie diets.
E
There is a strong correlation between diet and longevity in some species of animals.
This does not specify which type of diet increases longevity or identify the species in question. This may support doctors making some dietary recommendation to increase longevity, but not the one described on the basis of the study.
Summarize Argument
The author tells us that what people say about politics often contradicts their political behavior. The argument defines these concepts: what people say is that they want less government intervention, but what they do is vote out inactive politicians. The author tells us that what politicians do is pass laws that intervene in voters’ lives. We then get a sub-conclusion: “voters often reelect politicians whose behavior they resent,” meaning that people vote for active politicians who interfere with their lives, which they don’t like. This all supports the claim that people’s political talk and behavior differ.
Identify Argument Part
The claim that people tend not to reelect inactive politicians is a factual premise that supports a sub-conclusion (that voters reelect politicians they resent), which in turn supports the main conclusion.
A
It describes a phenomenon for which the argument’s conclusion is offered as an explanation.
The claim that people don’t reelect inactive politicians is not explained by anything else in the argument. It’s just stated as a stand-alone factual claim.
B
It is a premise offered in support of the conclusion that voters often reelect politicians whose behavior they resent.
This is an accurate description of the claim that people don’t reelect inactive politicians. The claim helps to support the idea that voters reelect politicians they resent, which is a sub-conclusion that supports the main conclusion that political talk and behavior differ.
C
It is offered as an example of how a politician’s activity consists largely in the passage of laws whose enforcement interferes with voters’ lives.
The author never offers an example of how politicians’ main activity is to pass laws that interfere with people’s lives. Also, the claim that people don’t reelect inactive politicians is a distinct factual statement from the interference claim.
D
It is a generalization based on the claim that people complain about government intervention in their lives.
The claim that people don’t reelect inactive politicians is not based on the claim that people complain about government intervention. They’re two totally separate statements.
E
It is cited as evidence that people’s behavior never matches their political beliefs.
The author does not claim that people’s political behavior never matches their beliefs, only that it sometimes doesn’t.