Logical reasoning PrepTest 152 · Section 1 · Question 12

This answer does nothing to explain the discrepancy in left- and right-brain strokes, or the frequency of diagnosing them. As far as we know, other health problems have nothing to do with strokes of either side of the brain.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Since doctors diagnose more left-brain strokes, it's likely that right-brain strokes are more likely to go undiagnosed.

Answer Anticipation:
Undiagnosed? Where'd that come from? Why can't it be that more strokes happen in the left side of the brain than the right side?

The author fails to rule out the possibility that more strokes occur in the left side of the brain than the right side. To strengthen this argument, the correct answer will probably do so, either by stating the number of strokes in both sides of the brain should be relatively even, or more strokes are expected to occur in the right side of the brain than the left side.

Answer Explanation:
While not definitive ("very likely"), it does increase the likelihood that strokes occur relatively evenly in both sides of the brain. If that's the case, and more left-brain strokes are diagnosed, it strengthens the conclusion that the right-brain strokes frequently go undiagnosed.

Key Takeaway: If an answer choice is neutral, or, in other words, if different ways of interpreting it would change it from being a correct to an incorrect answer, it can be eliminated in Strengthen and Weaken questions (but not Argument Evaluation questions). Here, for example, the answer stating that the symptoms are different requires an additional statement to know what impact it has on the argument. If right-brain stroke symptoms are harder to diagnose than left-brain stroke symptoms, then the answer has a different impact on the argument than if they're easier to diagnose.

While this answer might appear tempting by suggesting a reason that some strokes go undiagnosed, it doesn't explain why those diagnoses skew towards one side of the brain. Presumably, the doctors good at diagnosing strokes would see just as many patients with left-brain strokes as right-brain ones.

A common trap answer! If it had stated that the right-brain stroke symptoms are harder to notice than those of left-brain strokes, then we'd have an answer. But since the answer is neutral—it just says they're different&mash;this doesn't strengthen the argument.

Another answer that would be correct with an additional piece of information. If this answer stated that right-brain strokes were more likely to be minor strokes, then this would strengthen the argument. However, since it doesn't connect minor strokes to either side of the brain, it doesn't impact the argument.