PrepTest 118

Incorrect. First, this answer only applies to some of the studies, not all of them. Second, without further information about the funding influencing the outcome, this answer wouldn't weaken the argument.

Incorrect. This answer isn't specific enough to have an impact on the argument. Maybe the variation is only .5%, so it's negligible and doesn't actually matter. Without knowing that it varies significantly and that the relevant conditions change in this location, this answer doesn't have an impact on the argument.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Dioxin from a mill is in the water where there are fish reproductive abnormalities. However, dioxin decomposes slowly, and fish return to normal during mill shutdowns. Therefore, dioxin likely isn't the cause of the abnormalities.

Answer Anticipation:
An infamous question! Despite being #12, this question is one of the most difficult LR questions the test has seen. It has a lot of concepts behind it, though, and really digging in and learning it can help you with the underlying concepts. If you really get this question down, the LSAT can't throw anything at you you can't handle!

First off, this argument does deal with correlations and causation, but it does so in an interesting way. It starts off in a manner that would make you think it commits a correlation/causation flaw—dioxin is present in water where fish have certain abnormalities. However, the argument zags when it reaches a conclusion that dioxin is unlikely to be the cause of these abnormalities instead of concluding that it is the cause.

How does it reach that conclusion? It brings up a situation where the effect goes away (fish hormone levels return to normal) despite the cause presumably still being present (the mill closed, but dioxin decomposes slowly in the environment). That's a classic method to weaken a correlation/causation argument—show a counterexample (effect without cause). These premises suggest that there's something else going on at the mill that is causing the abnormalities.

And that's the argument we need to weaken—this counterexample meant to undermine the causal relationship. How can we undermine a counterexample? By showing that it isn't really countering what it's meant to! Again, this counterexample was designed to show that dioxin is present when the reproductive abnormalities aren't, but it doesn't actually establish that dioxin is present—just that it degrades slowly in the environment. Any answer suggesting that the dioxin wasn't still present when the mill closed, despite the slow degradation, would weaken the applicability of that counterexample.

Answer Explanation:
It's easy to rule this answer choice out, but it deals with the presence of dioxin in the water, so you should have given it consideration. Based on this information, we know that dioxin may decompose slowly in the environment, but it doesn't stick around long because it gets washed away. Therefore, when the mill closes and stops releasing dioxin, that dioxin disappears from the environment around the mill within a few hours—the timeline for the fish recovering their hormone levels. This information calls the counterexample into question—the dioxin wasn't present in the water during those mill closures, so the restoration of the fish hormone levels might have been in response to lower levels of dioxin. In calling the counterexample that the author uses to undermine a causal relationship into question, this answer weakens the argument.

Key Takeaway:
Go back. Review this question. Then do it again. It includes a lot of high-level concepts about correlation, causation, and how to weaken those arguments. If you can thoroughly understand this difficult question, you can tackle any LR question the LSAT throws at you!

Incorrect. While some fish didn't recover, the overall population did, so a few outliers don't call the argument into question (they rarely do).

Incorrect. A connection can exist even if it's not understood, so this answer choice doesn't impact the argument. Similar answer choices are commonly offered as incorrect on the LSAT.