#7 - Researcher: Over the course of three decades, we

[Administrator]

Complete Question Explanation

Resolve the Paradox. The correct answer choice is (C)

The stimulus contains a fact set about the two bird populations—one captive and one wild—of the
same species of bird. Over a period of thirty years, the average beak size of the captive birds did not
change, while the average beak size of the wild birds decreased significantly. The correct answer
must account for the difference in beak size between the two groups of birds. More specifically, it
must explain why the average beak size of the wild birds decreased during the study period, while
the captive birds’ beaks did not.

Note that the stimulus does not contain a true paradox, just an odd situation that is presented without
explanation. The correct answer must explain how the situation came into being while allowing
both sides of the situation to be factually correct. It would be a mistake, for instance, to question the
finding that the average beak size of the wild birds decreased because the decrease is presented as a
fact in the stimulus. As in all Resolve questions, because you are not seeking to disprove one side of
the situation, look for an answer choice that contains a possible cause of the situation.

Answer choice (A): At first glance, this may seem to be an attractive answer. After all, if the smallbeaked
wild birds were easier to capture and measure, that would explain why wild birds were
observed as having smaller beaks. But the researcher never stated that wild birds had smaller beaks
in general; rather, their size decreased over time. If small-beaked wild birds had been easier to
capture from the beginning, this would suggest that the research was biased in favor of capturing
small-beaked wild birds from the very beginning of the study period. Even if this was the case, this
does not explain why the beak size decreased over time.

The key to Resolve questions is close reading. Answer choice (A) is attractive because it appears to
possibly explain the difference in beak size between the two groups of birds, but it actually provides
no explanation for the change in the beak size of the wild birds. Instead, it gives a reason why these
birds would have been consistently observed as having smaller than average beaks, which was not
the case. In short, this answer attempts to explain a difference with a similarity, which is always
incorrect in a Resolve question. You must make sure that the answer you select does not deviate from
the circumstances described in the stimulus.

Answer choice (B): Even if large-beaked wild birds were easier to capture and measure, why did
the researchers observe a decrease in their beak size? This answer provides no explanation, and thus
cannot be correct.

Answer choice (C): This is the correct answer choice. If changes in the wild birds’ food supply
during the study period favored the survival of small-beaked birds, then over time there would be
sufficient evolutionary pressure on beak size to gradually change it. As this answer choice explains
the difference in beak sizes, this answer choice is correct.

Some students might object to this answer because the situation seems unrealistic: during extended
periods of drought, for instance, birds with larger beaks are favored because larger beaks are more
helpful for opening hard seeds. However, remember that the question stem tells you that each answer
choice should be taken as true. Since this answer choice clearly states that changes in the food
supply favored the survival of small-beaked birds during the period of the study, you must accept that as true and then analyze what effect that would have.

Answer choice (D): Information about body size does not necessarily explain the difference in beak
size between the two groups of birds. Consequently, this answer choice is incorrect.

Answer choice (E): There are two ways to look at this answer. In the first, if researchers observed
a significant decrease in the average beak size of the wild birds, most likely they measured some
bird beaks on more than one occasion. But even so, that would not provide an explanation for the
researchers’ findings. The second way of looking at this answer is that measuring the beak of the
same bird more than once is at best a randomizing factor, and a random factor cannot explain what is
clearly a pattern of decrease. Regardless, under either scenario, this answer is still incorrect.

[prep88]

Hi everyone,

I can see that answer choice (C) resolves the paradox, but I don't understand why answer choice (E) is incorrect: if the researchers measured a birds beak on more than one occasion doesn't this resolve the issue? Immagining if they measured 50 beaks from which 35 of a single small-beaked bird found in different places. This will resolve right? Any ideas?

Thanks!

[Nikki Siclunov]

Hi prep88,

Thanks for your question. Answer choice (E) only states that they measured the beaks of some wild birds more than once. Yes, I suppose if they happened to measure the beak of Mr. Small Wild Bird 50 times and added those measurements to calculate the average, the wild birds would seem to have smaller-than-average beaks. The thing is, we have no idea how large were the beaks of those birds that they measured more than once. Absent that information, answer choice (E) cannot provide a suitable explanation for the scientists' findings, that is, we would need to make a series of unwarranted assumptions to make (E) work. By contrast, answer choice (C) provides an immediate and direct explanation, requiring us to assume little else.

Does that make sense? Let me know.

Thanks!

[prep88]

I see now! If we appply this principle to another RP question from this test: section 4, Q 26. This is a resolve X question. I thought that because of the uncertainty of how the medical condition interferes with digestion of those people above 65 and hence, cteating necessity to speculate further, this answer does not resolve the issue. That medical condition could have actually helped digestion and even further complicate the issue, right? Am I correct to see similarities between this two answer choices?

[prep88]

Any ideas?

Thanks!

[Robert Carroll]

prep,

Any condition that interferes with digestion per se creates a problem with it. "Interferes" is not something that could either be good or bad - it's definitely a problem, so it does not require further information to resolve the paradox. If instead the answer said "affects digestion" or something neutral like that, it would be open to the criticism you offer, but "interference" has no such ambiguity.

Robert Carroll

[prep88]

Thanks for clarification of the word! I see now! But I've found another one; February 1999, Section 1, Question 25. In this question the paradox is the mismatch of the percentage figures between the returned + defective garments (7%) and the actual recycled scrap (9%), we have 2% surplus clothing recycled. Than the answer choice (E) resolves the paradox, by the reasoning that the unsalable garment is recored by count but recycled garment is recorded by weight. However, according to our principle, namely the uncertainty whether which result has a bigger figure expressed in percentage, this shouldn't be true!??

Thak you!

[Adam Tyson]

Not sure I understand the question as you've asked it, particularly what principle you are referring to, but I'll take a stab at helping out with this one.

In the stimulus we have a definition of what is "unsalable" - it's the defects plus the returns. We also have two percentage figures - 7% are unsalable, 9% are recycled. What we don't have is any explanation of what those are percentages OF. Answer E provides that answer by telling us that the two figures are based on different calculations - 7% of the NUMBER of garments, but 9% of the total WEIGHT of the garments. By providing that the figures were calculated using different measures, that helps explain how the same pile of scrap garments can be calculated two different ways.

One could deduce that some of the garments being recycled were heavier than the average garment, so that they make up a higher percentage of the total weight than of the total number of units.

I'll admit that this didn't match my prephrase - I was looking for some additional category that gets recycled in addition to the unsalable garments (let's call those "undesirable" - not defective, not returned, just ugly). When that didn't appear, the percentages answer looked good to me as a second choice.

I hope that helped!

[prep88]

The thing is, we have no idea how large were the beaks of those birds that they measured more than once. Absent that information, answer choice (E) cannot provide a suitable explanation for the scientists' findings, that is, we would need to make a series of unwarranted assumptions to make (E) work. By contrast, answer choice (C) provides an immediate and direct explanation, requiring us to assume little else.

The principle that I was referring to is deduced from above; that if an answer choice does not directly and explicitly solve the issue (does not mention the size of beaks of the birds captured more than once and leaving the argument vulnerable to different possibilities, as whether those birds captured more than once could actually have had even bigger beaks than the other group under discussion), it cannot be the correct answer.

Similarly, in the case of recycled garments mismatch, even though the unsellable garments are recorded by count and recycled gaements are recorded by weight, it is not obvious that recycled garments are not more either in count or weight than the returned, and we have to make unwarranted assumptions, namely that the count and weight actually coincide but have different percentage figures!

Could you please explain the difference between these two answers?

Thanks a heap!

[nicolle828]

Hi Prep88,

This is a tough question. It is, however, different from the beak question and I would like to go over each of the answer choices to show you why. The stimulus explains that a clothing manufacturer reports that all of it's unsalable garments are those found to be defective by inspectors and those returned by retailers. The total amount of those two equals 7% of the garments produced. It then states that all of it's unsalable garments are recycled as scrap, but the amount recycled as scrap totals 9%. The question stem asks which of the answer choices can explain the 2% discrepancy.

Answer A discusses items with minor blemishes that will be sold wholesale so it does not apply to unsalable garments and is a loser. Answer B provides information about why some of the items are unsalable, but the stimulus states that all unsalable items are scraped so this information does not explain any discrepancy and is a loser. Answer C is similar to answer B in that it explains why some of the items are found unsalable by the inspectors, but like Answer B, those items are scraped no matter the reason and so does not explain the discrepancy thereby making C a loser. Answer D discusses an increase in the total number of items produced, but this number would increase both salable items and unsalable items so does not explain the discrepancy and is a loser. Answer E tells us that the unsalable items are measured by count, but recycled garments are measured by weight. Imagine that a lot of heavier garments are unsalable, the the count could be 7% of the garments produced, but their weight could easily be 9% of the garments produced. So Answer E explains the discrepancy and is the correct answer.

I hope that helps!!

Nicolle