The Community Center Notice
The Riverside Community Center posted this notice on February 10: "Beginning March 1, weekend hours at the center will change from 9 a.m.–1 p.m. to 8 a.m.–3 p.m. The new hours apply to the fitness room and computer lab only. The front desk, childcare room, and pool will keep their current weekend schedule. The change follows a member survey in which 62% of 150 respondents said they wanted earlier weekend access." A member named Dara reads the notice and says, "Most members want the doors open at 8, so I can drop my son at childcare before my shift." The center has 1,240 members on its rolls.
1. Dara plans to drop her son at the childcare room at 8:15 a.m. on Saturday and then work out. Based only on the notice, what will actually happen, and which specific wording limits her plan?
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What happens: Dara can use the fitness room at 8:15, but the childcare room will still be closed until 9 a.m., so her plan fails.
The limiting wording: "The new hours apply to the fitness room and computer lab only" and "The front desk, childcare room, and pool will keep their current weekend schedule."
Reasoning: The early opening is not a building-wide change. Two separate lists are given - what changes (fitness room, computer lab) and what does not (front desk, childcare, pool). Dara merged the two lists into one, which the text never does.
2. A coworker says, "This proves 38% of the members opposed the change." Evaluate that claim.
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The claim is not supported, on two separate grounds.
- Wrong group. The 38% is 38% of respondents, not of members. 62% of 150 respondents = 93 people who wanted earlier access; 57 respondents did not say that. The other roughly 1,090 members are simply unknown.
- Wrong conclusion. Not asking for earlier access is not the same as opposing the change. A respondent may have skipped the question, wanted later hours instead, or had no opinion.
What the notice actually supports: most respondents wanted earlier weekend access. Anything about "members" as a whole requires assuming the 150 respondents look like all 1,240 members, which the text never states.
3. The center director wants to know whether "most members want earlier weekend access." What single piece of additional information would be most useful, and why is it more useful than simply counting more survey responses?
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Most useful: how the 150 respondents were selected - for example, whether they were a random sample of all 1,240 members or a sign-up sheet left at the front desk.
Why selection beats volume: A sign-up sheet at the front desk is answered mostly by people who already come on weekends; adding 500 more responses collected the same way repeats the same bias. A random sample of about 150 from 1,240 is large enough to estimate the whole membership reasonably well, but only if everyone had an equal chance to be picked.
What to look for in the answer: if selection was random, the 62% can reasonably be projected to members. If it was self-selected, the 62% describes only the people who chose to answer.