Logical reasoning PrepTest 121 · Section 1 · Question 3

Incorrect. We already know that they were accurate most of the time, and we don't know how often they were actually watched, so this answer doesn't add anything to the argument.

Incorrect. What happened after the experiment wouldn't have an impact on the experiment itself.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Study - People were 60% accurate in determining if they were being watched
Conclusion - Some people have a "sixth sense" that allows them to know when they're being watched

Answer Anticipation:
Whenever an argument is based on a study, you should start by considering a sampling flaw, and a correlation/causation flaw.

For the sampling flaw, there's no discussion of the sample here, so there's no reason to believe it isn't large and representative. And even if it weren't, the conclusion states that "at least some" people have a certain ability, so there's no need for the sample to be representative anyway!

For the correlation/causation flaw, does this argument have a causal conclusion? Yes, it does—a "sixth sense" is said to be the cause of detecting when people are watching. Is it based on a correlation? Yep—people were able to identify when someone was watching them with a 60% accuracy rate. Since this argument has a correlation/causation flaw, we can strengthen it by:
(1) Eliminating an alternative cause
(2) Have more examples of cause and effect going together
(3) Have a "control group" (which would be hard to have here since you can't detect if someone has this "sixth sense" without running them through a similar study!)

Answer Explanation:
This answer presents more examples of the ability in a different context, strengthening the argument by strengthening the correlation/the instances of this ability being demonstrated.

Key Takeaway:
When an argument relies on a study, start by considering a sampling flaw and a correlation/causation flaw. However, if the conclusion doesn't rely on the sample being representative (here, the conclusion is about "at least some" people, which is established with any examples being shown), then you can assume that the flaw in the argument won't be a sampling error!

Incorrect. This answer suggests an alternative cause—they couldn't detect being watched by a "sixth sense" but because they could hear the person outside watching them. Since it raises an alternative cause, it weakens the argument.

Incorrect. As we noted in the Anticipation, the sample being representative doesn't matter, as the conclusion only needs some examples in order to justify itself. That said, this answer would establish a reason to believe the sample isn't representative, which would cut against the argument.