Self-study
To cut costs, a high school modified its air-conditioning system to increase its efficiency. ███ ████████ ███████ ████████ ██████ ███ ████████ ██ ███ ██████ ███ ██ ████████ ██ ██ ████████ ███████████ █████ █████ ███ ████████ ██ ███ █████████ █ ██ ███████ ████████ ██ ███ ██████ ██ ██████ ██ ███ ██████ █████ ███ █████████ ████ █████ ████ █ ████████ ██ ████████ ███ ████ ██████ ████
Summary
The author concludes that a decrease in humidity can cause illness. She points to a correlation between a decrease in humidity and nurse visits at a particular high school.
Notable Assumptions
This is a cookie-cutter correlation-to-causation argument, so the author predictably makes several assumptions.
(1) She assumes there is no alternative explanation for the increase in nurse visits.
(2) She assumes the nurse visits were specifically caused by illness instead of some other reason.
We would also normally be looking for reverse causation, but the author defends against this potential issue by telling us the nurse visits took place after the decrease in humidity.
12.
The argument depends on assuming █████ ███ ██ ███ ██████████
a
At least some ██ ███ ██████ ██ ███ ██████ █████ █████ ███ ██████ ███ ████████ ████ ███ ██ ████████
This answer choice touches on the assumption that the nurse visits were caused by illness. If we negate this answer choice to say that none of the visits were caused by illness, the connection between humidity and illness is destroyed.
b
Most of the ████████ ██ ███ ████ ██████ ████████ ████ ███ ████████ ██ ███ █████████
This answer choice is too strong. We only need at least some of the students to have suffered from the decrease in humidity, not a majority.
c
It takes 24 █████ █████ █ ██████ ██ ████████ ████ █ █████ ███ ████ ██████ ██ ███████ █████████
This answer choice could only hurt the argument. If it takes a full 24 hours to show viral symptoms, it would be unlikely for students sick with viruses to have already caused a 25 percent increase in nurse visits, ruling out viruses as the cause of the nurse visits.
d
A decrease of ██ ███████ ██ ███ ████████ ██████ ██ ████████ ██ ██ ███████ ██ █████ ███████████ ██ ████████ ████
This answer choice is far too strong. An 18 percent decrease in humidity doesn’t have to cause exactly a 25 percent increase in illness; it could be higher or lower, and the argument would still work.
e
Modifying the air-conditioning ██████ ██████ ██ ██ ██ ███████████ ███ ██ ███ ██████
The information about cutting costs is purely contextual and has no bearing on the conclusion. Regardless of whether or not it saved money, the modified AC system and subsequent drop in humidity very well could have caused the nurse visits and an increase in illnesses.