The Vending Machine Survey
A student council wants to know whether to replace the school's two vending machines with healthier options. A council member proposes the inquiry question: "Should we get rid of the vending machines?" The advisor notes that this question can be answered yes or no without gathering any evidence, and that it bundles several separate issues together: nutrition, cost, student satisfaction, and revenue for the school. The council has four weeks, a budget of $150, and access to about 900 students across three lunch periods. One member suggests simply polling their own homeroom because it is convenient. Another wants to ask the principal what to do and treat that as the answer.
1. Rewrite the council's inquiry question so it is researchable and evidence-oriented, and explain what makes your version better than the original.
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A stronger question would be: "How would replacing the current vending machine stock with healthier options affect student purchasing behavior, student satisfaction, and monthly machine revenue at our school?" This version is better for three reasons. First, it is open-ended rather than yes/no, so it requires evidence instead of an opinion. Second, it names the variables to be measured (purchasing behavior, satisfaction, revenue), which makes the investigation design concrete. Third, it acknowledges trade-offs, which matches the council's real decision. The original question also smuggled in a value judgment ("get rid of") and combined nutrition, cost, and satisfaction without separating them. A good inquiry question should be answerable with data the team can actually collect in four weeks on $150. My version passes that test; the original does not, because no amount of data collection would resolve a vague yes/no preference question.
2. A member proposes polling only their own homeroom. Evaluate this sampling choice against the council's goal.
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Polling one homeroom is a convenience sample and is very likely biased. A single homeroom is not a random slice of 900 students: it may overrepresent one grade, one academic track, or one friend group, and students in the same homeroom share schedules and peer influences. If that homeroom happens to contain mostly students who bring lunch from home, the results would misstate demand for vending machines entirely. The council's goal is to inform a decision affecting all students across three lunch periods, so the sample must reflect that population. A better approach within the budget: randomly select students from each lunch period (for example, every nth student entering the cafeteria) to get roughly proportional representation, and record grade level so the council can check whether the sample matches the school's composition. Convenience is a practical constraint, but it should shape how the sample is drawn, not who is excluded.
3. Another member says the council should just ask the principal and accept that as the answer. How should the council respond, and what role, if any, should the principal play?
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Accepting the principal's preference as the answer replaces inquiry with deference. The principal's view is a single stakeholder opinion, not evidence about student behavior, satisfaction, or revenue. It may be useful context, but treating it as the finding would defeat the purpose of a student-directed inquiry and would likely produce a decision that ignores student demand. A reasonable response: thank the member, then explain the distinction between stakeholder input and data. The principal can legitimately play several roles - clarifying constraints (contract terms, nutrition policy, budget authority) and reviewing the final recommendation - without supplying the conclusion. The council should still collect its own evidence and present it to the principal as part of a recommendation. If the principal holds decision authority, that is a fact about implementation, not a substitute for the investigation.