PrepTest 141, Section 4, 17. A positive correlation has been found…

How will the right answer fit in terms of support and conclusion?

Only the right answer will add support for disagreeing with the conclusion, or for the opposite conclusion.

Highlight the main conclusion in the passage, if there is one:

the soot itself probably does not cause this ailment

[BACKGROUND]. However, [CONCLUSION], since [SUPPORT].

Everyone recognized the pattern in this argument from just the first three words, right? “A positive correlation” tells you clearly this author is going to make a conclusion about cause-and-effect. In this case, the conclusion says the correlation does NOT mean there’s cause-and-effect, so the right answer will support that the “soot” causes “this ailment”.

Map the wording of the answers to the wording of the passage:

(A) …but little if any soot in the air, the frequency of the ailment is just as high…

If you take away the cause, that should mean the effect goes away too. So if there’s no soot but “the ailment” is still around, that actually hurts the cause-and-effect claim. We want an answer that supports the soot causing the ailment.

(B) If the ailment rarely occurs…

Haha this is just explaining how cause-and-effect works. Cool story, but we all knew that already. Since this isn’t adding new evidence, it can’t be the right answer.

(C) …but little other air pollution, the frequency of the ailment is at least as high…

This answer says “the ailment” sticks around if soot sticks around, even if you get rid of the real cause the author says is behind it. That definitely gets me to disagree with the author. You gotta love how every part of the passage is brought into this one without anything new coming in.

(D) …then it is possible that two or more of those pollutants each causally contributes…

This only says a correlation makes it “possible” that there’s cause-and-effect. Like (B), you knew that before you ever decided to become a lawyer. Evidence that something is “possible” isn’t strong enough to support the conclusion anyway.

(E) …there are generally also high concentrations of other forms of pollutions…

We want an answer that supports the cause-and-effect relationship between soot and the ailment. How would this do that? It doesn’t. It brings in a whole new possible cause, which doesn’t map to anything in the passage, and only confounds things further.

(C) is the correct answer.

Common pattern/s in this question: Recognizing that the argument is about cause-and-effect keeps you focused on what the right answer has to say and prevents getting distracted by answers that “seem to make sense.” Even just seeing support or background about a correlation is enough to tell you this pattern is happening.