PrepTest 131, Section 3, Question 12
To cut costs, a high school modified its(56 more words not shown)
The argument depends on assuming(5 more words not shown)
- AAt least some(16 more words not shown)
- BMost of the(12 more words not shown)
- CIt takes 24(15 more words not shown)
- DA decrease of(17 more words not shown)
- EModifying the air-conditioning(10 more words not shown)
Reading the argument
The school makes its air conditioning more efficient, and the air becomes less humid. Before treating that as harmful, I'd want to know how humid it was to begin with. Making an extremely humid room less humid is different from making an already dry room drier. The percentage change alone doesn't settle its effect.
Then visits to the nurse increase. That gives us something to investigate, but was the humidity responsible? Perhaps the cafeteria served contaminated food. Perhaps a cold was spreading through the school. Even an unusually demanding fitness test in gym class could have sent students to the nurse with symptoms. The increase could follow the air-conditioning change without being caused by it.
So when the author says this shows that lower humidity can make people ill, I'm not yet convinced. The timing doesn't identify the cause.
What we’re looking for
For an assumption the argument depends on, my first thought is something addressing those alternative explanations. Let's look for a claim the author needs in order to use the nurse visits as evidence about illness caused by lower humidity.
Working the answers
- ACorrect
This catches a more basic issue: were any of those visits for illness at all? Suppose students went to the nurse for scraped knees from playing basketball. More nurse visits would not then establish more illness, whatever happened to the humidity.
The author needs at least some actual illness behind the visits to use them as evidence that the humidity change made people sick. That alone doesn't establish the cause—we could still ask about the cafeteria or a spreading cold—but it is a necessary part of this argument's evidence.
- B
Most students need not have suffered. A 25 percent increase in nurse visits is an increase relative to the previous number of visits, not a claim that 25 percent of all students, let alone a majority, became ill. The conclusion only says reduced humidity can cause illness; it doesn't require harm to most students.
- C
The passage doesn't establish that the proposed illness was caused by a virus. Nor does the report coming 24 hours after the humidity change establish a virus's incubation period. The argument can make its claim without assuming this precise biological timing.
- D
A change in the number of nurse visits is not the same as an equal percentage change in each person's chance of illness. People could visit for different reasons or make multiple visits. The author does not need this exact numerical relationship to claim that lower humidity can make people ill.
- E
The argument's conclusion concerns illness, not cost savings. The modification could save money and have an unwanted health effect at the same time. Its success or failure at reducing costs doesn't determine whether the nurse visits provide evidence for the conclusion.
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