PT123.S2.Q21

PrepTest 123 - Section 2 - Question 21

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Driver: My friends say I will one day have an accident because I drive my sports car recklessly. But I have done some research, and apparently minivans and larger sedans have very low accident rates compared to sports cars. So trading my sports car in for a minivan would lower my risk of having an accident.

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21.

The reasoning in the driver's argument is most vulnerable to criticism on the grounds that this argument

a

infers a cause from a mere correlation

This describes the driver's flaw. The driver observes a correlation between the type of vehicle someone drives and their accident rate. Minivan drivers have fewer accidents than sports car drivers. From this correlation, the driver infers a causal relationship: he believes switching to a minivan would cause his accident risk to drop. But a correlation between two things doesn't prove that one causes the other. As discussed in the anticipation, the lower accident rate for minivans could be explained by the driving habits of the people who choose minivans, not by anything about the vehicle itself.

56%
b

relies on a sample that is too narrow

There's no sample problem here. The driver cites research about accident rates for minivans versus sports cars, but we have no reason to think this research is based on a narrow or unrepresentative group. The driver doesn't say, for example, "I looked at accident rates for one specific model of minivan in one specific city." He references general accident rate data.

1%
c

misinterprets evidence that a result is likely as evidence that the result is certain

The driver doesn't treat a likely result as though it were certain. His conclusion is only that switching to a minivan would "lower" his risk of an accident, not eliminate it entirely. He's not claiming he'd never have an accident in a minivan. So there's no leap from "likely" to "certain" happening here.

17%
d

mistakes a condition sufficient for bringing about a result for a condition necessary for doing so

This describes confusing a sufficient condition with a necessary condition. For example, if the driver argued: "Driving a sports car guarantees you'll have an accident. My friend had an accident. So my friend must drive a sports car." That would be treating a sufficient condition (driving a sports car) as though it were necessary (the only way to have an accident). But the driver's argument doesn't involve sufficient or necessary conditions at all. The premise is a statistical comparison, not a guarantee, and the conclusion is about lowering risk, not about what's required or guaranteed.

25%
e

relies on a source that is probably not well-informed

The driver mentions doing "some research," but we don't know anything about where this research came from, so we have no basis to say the source is probably not well-informed. Maybe the research comes from a reputable government agency, maybe it comes from a blog. We just don't know.

1%

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