Logical reasoning PrepTest 118 · Section 4 · Question 11

Incorrect. This answer would set a baseline to compare the Cod Bay cod to. If the normal deformity rate is 3%, then cod bay is normal and the chemicals probably didn't cause the deformities. If the normal deformity rate is 0.3%, then there's something going on in Cod Bay.

Incorrect. Similar to (A), this answer would set a baseline to compare the 3% to, letting us know if the chemicals coincided with an increased rate of deformity. If the deformity rate went up shortly after the chemicals started to be dumped, then the relationship is strengthened; if the rate didn't increase, then it's weakened.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Bizarro Argument Evaluation

Stimulus Summary:
Chemicals known to cause genetic abnormalities were dumped in Cod Bay. Now, 3% of cod have a deformity that stops people from buying them. The fishing industry is suing those who dumped the chemicals claiming it caused the deformities.

Answer Anticipation:
While the argument does establish that the chemicals are known to cause genetic mutations, the causal conclusion here—that the chemicals caused this specific deformity—is based on a correlation. Maybe the genetic mutations caused by the chemicals don't manifest as deformed fins, or maybe the chemicals were released at too low a level to cause genetic abnormalities.

When anticipating answers in an Argument Evaluation question, it can be helpful to think through a Strengthen/Weaken lens—the correct answer should highlight a piece of information that can either strengthen or weaken the argument, depending on which direction it goes. So since this Bizarro Argument Evaluation question deals with a correlation/causation flaw, we should think about the common answers to Strengthen/Weaken questions, and any answer that hints at one of them should be eliminated:

Discuss an alternative cause; discuss more examples or counterexamples; discuss reversed causality (unlikely here); provide direct evidence of causality.

Answer Explanation:
The argument is over whether the chemical waste caused the deformities in the Cod Bay cod, thus resulting in economic harm to the fishing industry. Even if the deformed cod don't pose a health risk, people could still shy away from buying them because they're afraid they pose a health risk, or they just look unappetizing. Since any health risk is out of scope of the argument (again, since it's already been established that people are not buying the cod because of the deformities), the answer to this question wouldn't help evaluate the argument, so it's correct.

Key Takeaway:
Argument Evaluation questions can be viewed through a Strengthen/Weaken lens. Answers that help in evaluating the argument should highlight information that can strengthen and/or weaken the argument, depending on the specifics. This also means that we can use our generic anticipations for Strengthen/Weaken questions in this question type.

Incorrect. This answer choice asks a question that speaks to a potential alternative cause for the deformities, thus providing evidence that would help either strengthen or weaken the conclusion. If the cod are susceptible to a disease that causes deformities, that might be the culprit instead of the chemicals.

Incorrect. Similar to (D), this answer choice asks a question that speaks to a potential alternative cause for the deformities, thus providing evidence that would help either strengthen or weaken the conclusion. If other gene-altering pollutants are present in the Bay, then they could have caused the deformities instead of the chemicals in question.