"Surprising" Phenomenon
Why have auto thefts dropped dramatically in cities where car owners have the antitheft device installed, even though only a small % of car owners in those cities have installed the device?
Objective
The correct answer should help explain how only a small proportion of cars being equipped with antitheft devices can still lead to a significant decrease in the car theft rate.
A
Car thieves will tend to be less cautious if they are unaware that a car they have stolen contains a homing beacon.
But there’s still only a small % of cars with the device. Car thieves might be less cautious if they don’t know about these devices, which might mean these thieves get caught, but how could this dramatically decrease overall theft rates?
B
Typically, the number of cars stolen in cities where the homing beacons are in use was below average before the device was used.
We’re trying to explain how theft rates could have decreased. Whether theft rates started below, at, or above the average theft rates for cities doesn’t explain how those rates could have declined dramatically.
C
Before the invention of the homing beacon, automobile thieves who stole cars containing antitheft devices were rarely apprehended.
Even if we interpret this answer as suggesting thieves today are more frequently apprehended, wouldn’t we expect only a small proportion of thieves to be caught, since the device is installed in only a small proportion of cars? How could this significantly decrease cars stolen?
D
A large proportion of stolen cars are stolen from people who do not live in the cities where they are stolen.
We know only a small % of cars have the device installed in the relevant cities. Whether thieves live in other cities doesn’t affect our expectation that a small % of cars with the device should have only a small impact on overall theft rate.
E
In most cities the majority of car thefts are committed by a few very experienced car thieves.
If only a few car thieves are responsible for a large portion of car thefts, catching only a few car thieves can lead to a dramatic decline in thefts. This is how the devices could decrease thefts significantly despite being in only a small % of cars.
"Surprising" Phenomenon
Some areas outside of a conservation park have substantially higher populations of certain bird species than the park does.
Objective
The correct answer will be a hypothesis that explains why certain species are more prevalent outside the park than inside the park. The explanation must account for some quirk about the species themselves, or some quirk about the park that makes it less hospitable to these species than one would assume.
A
Moose are much more prevalent inside the park, where hunting is prohibited, than outside the park, and moose eat much of the food that the birds need to survive.
The park has a moose problem, which reduces food available for the birds. This isn’t true of areas outside the park, hence why certain bird species make their homes there.
B
The researchers also found that some unprotected areas outside of the park have substantially higher numbers of certain reptile species than comparable areas inside the park.
Rather than clearing anything up about the birds, we also have to account for reptiles. We want something that addresses the surprising fact about birds.
C
Researchers tagged a large number of birds inside the park; three months later some of these birds were recaptured outside the park.
Why did the birds leave? We’re looking for something that tells us why birds prefer to live outside the park.
D
Both inside the park and just outside of it, there are riverside areas containing willows and other waterside growth that the bird species thrive on.
This points to a similarity between the two areas in question. We need a difference that helps explain why some birds prefer not to live in the protected park.
E
The park was designed to protect endangered bird species, but some of the bird species that are present in higher numbers in the unprotected areas are also endangered.
Why don’t those birds go into the park? Like (D), this is missing a comparative aspect between the park and the unprotected areas.