Logical reasoning PrepTest 109 · Section 1 · Question 6

Incorrect. The stimulus doesn't tie weight/volume during production to pollution, so this answer doesn't add anything to the argument since it's already compared the disposal weight and volume between paper and plastic.

Incorrect. While the author does bring up popular opinion, the conclusion isn't about whether that opinion is right or wrong—it's about whether plastic or paper does more environmental damage currently. As such, no answer about what the popular opinion is will affect this argument.

Incorrect. Other sorts of trash are out of scope—the conclusion limits itself to discussing the relative harm of these two types of products.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Recent study — Representative trash samples show that plastics make up a smaller proportion by both weight and volume than paper.
Principle — Regardless of material the same weight/volume of trash has the same environmental impact.
(Opposing point — Plastic does more harm to the environment than paper.)
Conclusion — Plastic use does less harm to the environment than paper.

Answer Anticipation:
This argument has two features that suggests specific flaws—a study is done and a comparative conclusion is drawn.

Studies are associated with sampling flaws and correlation/causation flaws. Here the study notes that it looked at "representative" areas so a sampling flaw is unlikely. And while the conclusion is causal ("harm" involves cause/effect) there's a causal premise that can support it—that second statement establishes a means to determine relative harm.

With that line of thought leading to a dead end let's move on to considering the comparative conclusion. When that happens we need to see if the premises allow that comparison to be drawn. Here the conclusion is about the relative harm to the environment of plastic use vs. paper use. However the only point of comparison between the two is on the environmental harm done by their disposal. The comparison in the conclusion is much broader than the comparison established in the premises leading to a flaw.

So this argument is failing to consider that while paper is harming the environment more during disposal plastics are doing more harm to the environment at other times such as production or use. To strengthen this argument then we should look for any answer that establishes paper doing more harm to the environment than plastics during other stages of the product's life. An answer establishing that the two do the same damage would also potentially strengthen this argument as if everything else is equal but the disposal of paper is doing more damage then paper is more damaging than plastics.

Answer Explanation:
This answer establishes that during another portion of the "product lifetime" of paper and plastic products paper is more environmentally damaging than plastics. If this is the case then there's more evidence of paper's damage to the environment supporting the broader comparison in the conclusion than in the premises.

Key Takeaway:
When an argument concludes a comparison check to see if the premises are sufficiently broad to support the comparison. Here the premises were limited to comparing one aspect of the conclusion leaving open the possibility that other aspects would cut in the other direction.

Incorrect. The stimulus notes that the study was done in "representative" areas of the country and the conclusion is about "nationwide." As such the argument speaks in averages and variations between the country are immaterial.