Self-paced
In Yasukawa's month-long study of blackbirds, the percentage of smaller birds that survived the duration of the study exceeded the percentage of larger birds that survived. ████████ ██████████ ██████████ ████ ████ ██ █ ███████████ ██ █ ███████████ ███████ ██ ████████ ████ █ ██████████ ██████ ██ ████████ █████████ █████ ███████ ██████████ ███ █████████ ███████ ████ ██████ █████
Argument Structure
Yasukawa concluded that size determines survival chances. Specifically, he concluded that smaller is better (for survival). Our author thinks this conclusion is wrong because age is a potential confounding factor. Smaller birds are younger birds, so perhaps the survival rates Yasukawa observed are actually due to age-related factors.
In short, the author accuses Yasukawa’s study of not controlling for age.
3.
The statements above, if true, ███████ █████ ███ ██ ███ █████████ ███████████
a
Among the blackbirds ████ ████████ ███ ██████████ ██████ █████ ███ ██ ████████ ███████ ████ ███ ████
Smaller blackbirds are generally younger than larger ones, and smaller birds survived the study more often than larger birds, so we have active reasons to think (A) is false.
b
Larger blackbirds of █ █████ ███ ███ ████████ ████ ██████ ██ ███████ ████ █ █████████ ██████ ████ ███ ███████ ██████████ ██ ███ ████ ████
(B) says the relationship between size and survivability must be reversed, when in reality it could also be nonexistent.
Yasukawa thinks smaller is better when it comes to survival, but Yasukawa is probably mistaken because they didn’t control for age. That means “smaller probably isn’t better,” which doesn’t mean “smaller is probably worse.”
People with freckles aren’t smarter than people without freckles. But that doesn’t mean they’re stupider. It’s just that freckles have nothing to do with intelligence.
c
Among blackbirds of ███ ████ █████ █ ██████████ ██ ███ ████████ ████ ███ ████████ █ ██████████ ██ ███████ ██ ████████ ████ █ █████████ ███████
For the author’s age-based objection to be relevant, there really should be relevant survivability differences between birds of different ages, controlling for size. But (C) says the opposite.
d
Among blackbirds of ███ ████ ████ █ ██████████ ██ ████ ███ ███ ████████ █ ██████████ ██ ███████ ██ ████████ ████ █ ██████████ ███████
(D) is appropriately weak, and relies on the idea that Yasukawa’s conclusion is probably mistaken (which is allowed because this is an MSS question).
Yasukawa thinks smaller is better for survivability, but that’s probably not true because they didn’t control for age. If they did control for age, then, the size-based effect might dissipate.
e
With a larger ██████ ██ ███████████ ███ ██████████ ██ ███████ █████ ████ ███████ █ █████████ ██████ █████ ██ ███ ████ ██ ███ ██████████ ██ ██████ █████ ████ ████████
(E) ignores the author’s primary complaint: Yasukawa’s sample didn’t control for age.
If this larger sample also didn’t control for age, we’d have no reason to believe the results would be any different.