"Surprising" Phenomenon
When traffic lights and street markings that are designed to increase street safety were removed, the number of accidents on the street did not increase as expected, but instead diminished greatly, even though the amount of traffic on the street did not decrease.
Objective
The right answer will describe a safety benefit to the removal of the traffic lights and street markings. The benefit will help explain why accident numbers went down after the traffic lights and street markings were removed.
A
People often disregard traffic lights and street markings.
This doesn’t matter to us. If people were frequently disregarding the traffic lights and street markings anyway, we would expect little change when they were removed. There was a substantial change, though, and we want to know why.
B
The lack of traffic lights and street markings caused drivers to drive more cautiously.
This is a safety benefit that came from removing the traffic lights and street markings: drivers started driving more cautiously. It’s easy to see how more cautious driving would lead to decreased numbers of accidents on the street.
C
Most drivers were not aware that traffic lights and street markings had been removed.
This doesn’t help us. Whether or not most drivers were aware of the change, the number of accidents on the street decreased. We want to know why.
D
Traffic lights and street markings are intended to have benefits in addition to those related to safety.
This doesn’t matter to us. We’re interested in the safety implications of having or not having traffic lights and street markings, not any other potential benefits.
E
Drivers were given advance notice that the traffic lights and street markings would be removed.
This doesn’t help us. Drivers knowing that the change was coming does not explain why the number of accidents decreased.
Summary
Some advertisers offer free home computers to certain consumers. Ads play continuously on these screens. Information about consumers’ browsing patterns is sent to advertisers, allowing them to transmit information that fits the consumers’ interests. Advertisers can afford to offer these free computers because of the increased sales generated by precise targeting of ads.
Strongly Supported Conclusions
Many consumers who use the free computers purchase products advertised to them on their computers.
A
At least some consumers who use a computer offered free of charge by advertisers for browsing the Internet spend more money on purchases from those advertisers than they would if they did not use such a computer to browse the Internet.
This is strongly supported because we know that the ads are tailored to those consumers and we know that the computers generate additional revenue from sales that offsets the cost of the computer.
B
No advertisers could offer promotions that give away computers free of charge if consumers never used those computers to browse the Internet.
This is unsupported because there may be other schemes advertisers could use to figure out consumers’ interests outside of internet browsing patterns.
C
There are at least some consumers who browse the Internet using computers offered free of charge by the advertisers and who, if they did not use those computers to browse the Internet, would spend little if any money on purchases from those advertisers.
This is unsupported because it could be true that some of the consumers would have spent a lot of money on advertised products whether or not they had the free computers.
D
The advertisers would not be able to offer the computers absolutely free of charge if advertisements that accurately reflected the interests of the computers’ users did not play continuously across the computers’ screens whenever they were in use.
This is unsupported because it could be true that the advertisers would be able to offer the computers free of charge even if the ads played most of the time, but not continuously, across the screens when in use.
E
Consumers who use a computer offered free of charge by the advertisers can sometimes choose to abstain from having information about their browsing patterns sent to the advertisers.
This is anti-supported because is implied that the reason the computers are free is because they serve as a way for advertisers to collect information from browsing habits to send tailored ads to consumers.
Summarize Argument: Phenomenon-Hypothesis
The zoologist hypothesizes that prehistoric European cave bears were not exclusively herbivores. This is supported by observations about bears’ heavy nitrogen levels, which are higher in meat-eating animals. Bone samples from cave bears contained heavy nitrogen levels as high as those in blood samples from modern, meat-eating bears.
Notable Assumptions
The zoologist assumes that heavy nitrogen levels in animals’ bones and blood are similar. The zoologist also assumes that heavy nitrogen levels did not change over time in the prehistoric bear samples, and that heavy nitrogen levels in the ecosystem back then were comparable to current levels.
A
Plants can also absorb heavy nitrogen from a variety of sources other than rainwater.
This is irrelevant. The argument has already established that plants absorb heavy nitrogen, so the exact source of the heavy nitrogen doesn’t matter.
B
The rate at which heavy nitrogen accumulated in the blood of Ice Age herbivores can be inferred from samples of their bones.
This is irrelevant, since the argument doesn’t make claims based on the rate of accumulation of heavy nitrogen in tissue, only the concentration of heavy nitrogen.
C
The same number of samples was taken from present-day bears as was taken from Ice Age cave bears.
This is irrelevant, because the exact number of samples doesn’t really make a difference. Either there were enough samples to be representative or there weren’t—either way, it would be equally possible to have the same number of samples.
D
Bone samples from present-day bears fed meat-enriched diets exhibit the same levels of heavy nitrogen as do their blood samples.
This strengthens by providing a closer comparison between cave bears and modern bears. If modern bears’ heavy nitrogen levels are identical between blood and bone, it’s more reasonable to draw conclusions by comparing cave bears’ bones and modern bears’ blood.
E
The level of heavy nitrogen in the bones of any bear fed a meat-enriched diet is the same as that in the bones of any other meat-eating bear.
This is irrelevant, since we can already be confident that the heavy nitrogen level in the modern bear samples is representative of a diet that includes meat.