To evaluate the effectiveness of a newly launched online virtual training course, a nationwide fitness chain surveyed 500 members who voluntarily signed up for and finished the entire 12-week program. Finding that 88 percent of these participants achieved measurable increases in cardiovascular endurance, the company concluded that making the online training course available to all its members would significantly improve the overall physical fitness of its entire customer base. Which of the following identifies the most serious flaw in the argument's reasoning?
- It bases its conclusion on a sample of members whose voluntary participation suggests they may already be more motivated to exercise than the general membership.Cevap
- BIt assumes that improvements in cardiovascular endurance are equivalent to overall physical fitness across all athletic disciplines.
- CIt fails to consider whether individuals who are not members of the fitness chain would experience similar endurance gains from the course.
- DIt mistakes a condition that is necessary for achieving cardiovascular fitness for a condition that is sufficient to guarantee it.
- EIt presumes without warrant that high cardiovascular endurance directly causes an increase in long-term gym membership renewals.
Cevap
The argument relies on a sample of participants who voluntarily enrolled in and completed the course, introducing self-selection bias that renders the sample unrepresentative of the entire gym membership.
The correct response points out that the survey respondents voluntarily signed up for and completed the entire 12-week program. This self-selection process means the sample is composed of uncharacteristically motivated members. Because their results cannot be assumed to represent the broader, less-motivated general membership, extrapolating the program's success rate to all members is logically flawed.
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Self-Selection Sampling Bias
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