🧠 GRE Exam Prep

An argument concludes that a city's residents strongly prefer public transportation over private cars, based on a survey conducted only among commuters arriving at the central bus station. What is the most significant flaw in this evidence?

A The sample size of the survey was likely too small to be representative.
B The survey questions might have been leading or biased.
C The survey participants are a self-selected group, likely already favoring public transport.
D The survey did not offer incentives for participation.

✓ Correct Answer: Option C

This scenario represents sampling bias. Surveying only bus commuters skews the results, as this group is already predisposed to using public transportation, thus not representing all city residents.

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