Self-study
In 1990 major engine repairs were performed on 10 percent of the cars that had been built by the National Motor Company in the 1970s and that were still registered. ████████ ███ █████████████ ██████ ███ ███ ████ ████ ███ ████████ █████ ███████ ███ ████████████ ██ ███ █████ ███ ████ ████ ████████
Objective: Explain a Discrepancy
The stimulus tells us about major engine repairs on National Motor Company cars in 1990. In this year, major repairs were performed on 10 percent of still-registered cars from the 1970s, but only on 5 percent of still-registered cars from the 1960s. We would typically expect that older cars would be more likely to need repairs, so that's our discrepancy: why were the older cars relatively less likely to need repairs?
The correct answer choice will explain why this is the case. For instance, maybe only the most durable cars have stayed in use since the 1960s, or maybe there was a change in the manufacturing process that led to faultier engines in the 1970s. There are many possible explanations, but whatever its specifics, the correct answer will give us a relevant difference between 1960s and 1970s cars that explains our observations.
11.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████████
a
Government motor vehicle ███████████ █████████ ███████ ███ █████ ███████ ███ ██ ████ ██ ██ █████████ ███ ████████ ██████ █████ ██ █████████████
If this is true of all cars, it's not a difference between 1960s and 1970s cars. That means it can't explain the different outcomes for those two groups.
b
Owners of new ████ ████ ██ █████ █████ ████ ████ █████████ ████ ██ ██████ ██ ███ █████
If (B) were reversed, it could help explain the discrepancy. However, by telling us that newer cars are driven more carefully, (B) only deepens our confusion about why the newer cars still need more engine repairs.
c
The older a ███ ███ ███ ████ ██████ ██ ██ ██ ██ █████████ ███ █████ ██████ ████ ████████ ████ █████ ██████ ████ ██ ██████ ██ ████ ███ ███ ██ ██████████
Applied to our facts, (C) tells us that if a still-registered car from the 1960s has major engine trouble, it's more likely to be scrapped compared to a car from the 1970s. That would explain why older cars get fewer engine repairs: more of them just get discarded instead.
d
The cars that ███ ████████ █████ ███████ █████ ██ ███ █████ ████████████ ██████████ ██████ ███████ ████ ████ ███ ███████ ████ ███████████ ████ █████ ██ ███████ ███████
Like (B), (D) would be helpful if it worked in the opposite direction. However, saying that cars from the 1970s had simpler engines only makes it more confusing why they're more likely to need major engine repairs.
e
Many of the ███████ ████ ████ █████████ ██ ███ ████ ████ ███ ████████ █████ ███████ █████ ██ ███ █████ █████ ████ ████ ███████ ██ ████████ ███████ ███████████ ███ ████ ██████████
Without any information about 1970s cars, we can't know if this is a difference between 1960s and 1970s cars. That makes (E) a nonstarter for explaining our discrepancy—it doesn't let us compare the groups in question.