PrepTest 113

Incorrect. This answer is trying to get you to think that it's hinting at an alternative cause (some type of bad health), but there are two issues with that. First, it doesn't establish that it was just those with headaches who didn't participate in a health program. And second, it doesn't establish that failing to participate in a health program increases the frequency of headaches, or results in a malady that has that symptom.

Incorrect. The conclusion is about headaches generally, which would include both migraines and mild headaches. It also doesn't relate the frequency of monitor use to severity of headache.

Incorrect. Eyestrain is out of scope of the argument. And even if you assumed that eyestrain could cause headaches, that would strengthen the argument by explaining how the monitors lead to headaches.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Survey - Those who reported using monitors a lot are more likely to report having headaches
Conclusion - Monitors cause headaches

Answer Anticipation:
When we're dealing with a flaw-based question—which Weaken questions are, since we weaken arguments by attacking a flaw—we should look for features of arguments that tend to be flawed. Here, we have three.

First, there's a survey, so we should consider a Sampling flaw, and a Correlation/Causation flaw. The sample is of office workers, but the conclusion is about people generally. While there's probably no gap here—office workers are people, after all, and there's no reason to believe that they'd be medically different than others—we should at least have that in the back of our heads.

The Correlation/Causation flaw we should now consider overlaps with the second commonly flawed feature—a causal conclusion, which suggests the same flaw. Here, the conclusion is that monitors cause headaches, and this is based on those who worked a lot using a monitor also had headaches. That's a correlation, so there is a Correlation/Causation flaw here, and we can weaken it using the usual answer choices:
(1) Identify an alternative cause
(2) Counterexamples (cause without effect; effect without cause—though the stimulus already talks about headaches being more/less frequent, so counterexamples are already taken into account)
(3) Reversed causality (this makes no sense—headaches wouldn't cause someone to seek out a job that has them using a monitor)

Finally, the third element—the subjective nature of the responses. The workers were asked to estimate how much time they spent using a monitor and how frequently they suffered from headaches. That's self-reported information, and it could be wildly off! Any answer that brings up the possibility that this data is wrong—that there was a lot of overestimation in the headache group or underestimation in the other group—would undermine this argument.

Answer Explanation:
This answer addresses the self-reported nature of the data gathered in the survey. If those who suffered from headaches were more likely to overestimate their time spent using a monitor, then the correlation is based on faulty data, thus undermining the argument.

Key Takeaway:
The better you get at identifying elements that are related to specific flaws, the faster you can spot them, and the more of them you'll spot. This can be particularly important in a question such as this one, where there's a very glaring and common flaw in the form of the Correlation/Causation flaw. While that avenue can get you to the right answer (it is a bit of a counterexample), it goes through the flaw related to the self-reported nature of the data, and thus that's a faster and surer way to get this one right.

Incorrect. Assuming stress can cause headaches, this answer would eliminate an alternative cause, thus strengthening the argument.