PrepTest 125, Section 4, Question 14
Expert: A group of researchers claims to have(61 more words not shown)
The reasoning in the expert's(6 more words not shown)
- Afails to provide(7 more words not shown)
- Bcontradicts itself by(16 more words not shown)
- Cconcludes that a(16 more words not shown)
- Dinterprets an assertion(12 more words not shown)
- Etakes for granted(13 more words not shown)
Reading the argument
Maybe the antenna needs something else too.
The researchers say two features are required for equal performance at all frequencies: symmetry and a fractal structure. We don't need to know what a fractal looks like to follow that claim. Whatever those features are, the researchers say the antenna needs them. They haven't said the two features guarantee the result.
Think about saying that life requires water. Finding water without life wouldn't refute that requirement. Perhaps food or a suitable temperature is also needed. Likewise, an antenna could have both named features and still lack some other requirement for equal performance. Maybe the material matters too. That's a hypothetical possibility, not a new fact about antennas.
The expert treats the antenna's uneven performance as proof that the researchers are wrong. But this example could fit their claim perfectly: two requirements are met, another isn't, and the desired result doesn't happen.
What we’re looking for
For the flaw question, that is the confusion to look for. The expert treats things that are needed as though they are enough. We aren't being asked whether equal performance at every frequency is a useful goal; we're being asked whether this example disproves the researchers' claim.
Working the answers
- A
An undefined technical term doesn't prevent us from following the relationships here. We can understand 'this feature is required' without knowing the feature's technical details. The problem is the leap from having required features to being guaranteed equal performance, not the missing definition.
- B
Reporting a claim isn't the same as endorsing it. The expert tells us what the researchers claim in order to challenge it. There's no contradiction in saying, 'These people claim something, but I think they're wrong.' A contradiction would require accepting their claim and denying it, which isn't what happens here.
- C
The expert does more than say the researchers lack proof. The expert offers a particular antenna as evidence against their claim: it has both features but performs unevenly. The trouble is that this supposed counterexample doesn't violate what they actually claimed. C describes a different mistake, declaring something false just because it hasn't been established.
- DCorrect
The researchers identify necessary conditions, meaning features an antenna must have for the desired result. The expert treats those features as sufficient conditions, meaning features that guarantee the result. Failing despite having two requirements doesn't show that those features weren't required. Another requirement could still be missing.
- E
What happens at exactly 250 megahertz doesn't fix this reasoning. If an antenna works better at one frequency than another, it doesn't work equally well at all frequencies, regardless of how it performs at 250. The mistake is treating that unequal performance as a refutation of the stated requirements, not leaving out a third frequency category.
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