Q22 - A fourteen-year study of finches

[rpcuhk]

I was baffled when I read the question stem that asked for an answer that "must be assumed in order to justify the conclusion".
Anyone please help?

[ohthatpatrick]

Were you baffled because the question stem seems like a hybrid between Necessary and Sufficient assumption?

"must be assumed" is Necessary Assumption, while "justifying the conclusion" is typically only seen in Sufficient Assumption questions.

But, the overall gist of this question stem is still just "which of the following must be assumed" ... so it's Necessary Assumption.

There aren't too many of these exotic Necessary Assumption question stems out there, but here's another one
PT30, Section 2, #22
Which of the following is an assumption the argument requires in order for its conclusion to be properly drawn?

Still Necessary Assumption because they're still characterizing the assumption as required / must be assumed.

Let me know if this doesn't answer your question or if you have any questions about the actual problem.

[WaltGrace1983]

The Argument
(During droughts finches survive because they can crack large, hard seeds & during rain, there is more plants that produce small seeds)
-->
There is a correlation between climate and population (aka, more rain causes less finches)

My Thoughts
This argument is saying that, just because there is more of one plant's seeds during rain, the finches are less likely to survive. Ummmmm what? This argument is kind of like the following: Subway chicken sandwhiches are necessary for human survival. During the summer, we all eat lots of Subway chicken sandwhiches and everything is awesome and plenty of people make it through the summer. However, during the winter, Subway sells turkey sandwhiches. Therefore, more people die. The assumption in these arguments is something like "when the rain produces these small seeds, there are less large, hard seeds." The argument is assuming that more of one thing means less of the other.

(A) Out of scope. All we need to know here is that during droughts there are enough hard seeds to go around for all the finches. It doesn't really matter what else there is because the finches are doing fine during droughts.
(B) Correct. If more rain = less large hard seeds, then we can clearly see how this would be detrimental to the finch's survival. If we negate this and say that "rainy weather does NOT result in fewer large, hard, seeds" then this would mean that there doesn't seem to be as much of a relationship between climate and survival as peopel think
(C) Out of scope. In the argument, we are talking about survival and not about size. This seems like a trap answer for someone that was running out of time and saw "population SIZE of finch species) and went with it.
(D) Not necessary. We don't need to assume that there was as much of one kind of weather as the other. We are talking about what happens during those kinds of weather. It doesn't matter if that type of weather is any more or less frequent then the other type.
(E) Out of scope. We don't care if the seeds have to or don't have to be cracked open. The seeds are important not because of their "crackability" but because of their type and how available they are to these finches. There does not seem to be any correlation between "crackability" and survival