Logical reasoning PrepTest 143 · Section 1 · Question 20

Incorrect. Assuming the sample was representative, the stimulus supports the contention that 35% of people with schizophrenia will have abnormal brain subplates, not the other way around. The study would have had to have been on people with abnormal brain subplates (or all people, with that subgroup highlighted) to support this answer.

Incorrect. While damage to those connections might at least play a role in schizophrenia, there's no indication that the damage is repairable, so to call this treatment "promising" is out of scope.

Incorrect. While these two things are loosely correlated, there's no indication that one causes the other.

Incorrect. There's no indication that such damage is genetic, and there's no discussion of factors that could have led to schizophrenia in the other 65% of people, so this answer is unsupported.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Sample Ð Recently deceased people, some with schizophrenia
Finding Ð 35% of those with schizophrenia had a certain type of brain damage; 0% of those without schizophrenia had it
Context Ð The brain damage occurred before birth and has to do with brain connections

Answer Anticipation:
It's hard to anticipate and answer for this stimulus as it's essentially just a biology lesson along with a weak correlation between a certain type of brain damage and schizophrenia. As such, we should head into the answer choices to find one that matches with the details, knowing that the statements are relatively weak and some trap answers are going to get us to assume a causal relationship based on that correlation.

Answer Explanation:
This answer is very weak, which is great because the stimulus is also weak, based on correlations, and only about a minority of people in the study. Damage to the subplate is loosely correlated with schizophrenia, so it's possible that it causes it. That damage also happens before birth. So it's possible there's a cause of schizophrenia that occurs before birth.

Key Takeaway:
Correlation doesn't prove causation, but it's evidence for it. If two things aren't correlated, then they're not causally related. Correlation suggests that a causal relationship might be present.