Self-study
Some doctors believe that a certain drug reduces the duration of episodes of vertigo, claiming that the average duration of vertigo for people who suffer from it has decreased since the drug was introduced. ████████ ██████ █ ██████ ███████████ ████████ ██ ███ █████ █████ ███ ██ ███████████ ██████ ██ ███ ███████ ████████ ██ ████████ █████ ██ ███ ████████ ████ ███ ████ ███ ██ ██████ ██ ███ ████████ ██ ████████
Summary
The author counters the doctors’ belief by concluding that the drug has no effect on vertigo duration. She supports this by pointing to a phenomenon where, for the three months that people were forced to go without the drug, there was no significant change in vertigo duration.
Notable Assumptions
The author’s only support comes from this three-month phenomenon. She expected, if the drug were helping vertigo duration, to have seen a significant change. This must be true for her conclusion to be supported by her premises.
13.
Which one of the following ██ ██ ██████████ ████████ ██ ███ █████████
a
If a drug ████ █ ██████████ ██ ███ ████████ ██ ████████ █ ███████████ ████████ ██ ████ ████ █████ ████ ██████ █ ███████████ ██████ ██ ███ ███████ ████████ ██ ████████
This is necessary for the conclusion. If negated, this would destroy the argument: what if three months isn’t enough time to see a significant change, but the drugs are still helping?
This is also a sufficient assumption.
b
If there were ███ ██████ ██ ███ ███████ ████████ ██ ███████ █████ ███ ████████████ ██ ███ █████ ██ █████ ████ ████████████ ████ ███ ████ ███ ██ ██████ ██ ███ ████████ ██ ████████
This weakens the argument. We know that there has been a change in average vertigo duration since this drug has been introduced, so (B) would let us infer that the drug has an effect on vertigo—the opposite of our conclusion.
c
A period of ████ ███████ ████ █████ ██████ █████ ███ ████ ████ ██████ ██ ███ ██ ███████ ███████ ███ ████ ███ ██ ██████ ██ ███ ████████ ██ ████████
If negated, this does not wreck the argument. It’s fine if more time would have been better; the argument can survive that as long as three months is enough to judge whether the drug has an effect.
d
Changes in diet ███ ███████ ██████ ███ ███ ███████████ ███ ███ ██████ ██ ███ ███████ ████████ ██ ███████ █████ ███ ████████████ ██ ███ █████
The negation of (C) would strengthen our argument, and that’s the opposite effect that we want from a negation. Like (B), this weakens our argument, because it eliminates a possible alternative cause for the change in average vertigo duration.
e
There are various ███████████ ███████ █████ ████ █████ ████ ████████ ███ ████████ ██ ███████ ███ ████ ██████ ███ ██████ ████ ███
We do not need drugs to be the only factor involved in decreasing vertigo duration. The argument is concluding that a specific drug is not decreasing vertigo duration, and this could be true regardless of how many factors there are.