PrepTest 104, Section 1, Question 26

What we’re looking for

Working the answers

• A

  A few successful patients resemble the few matching dreams, and both conclusions caution against drawing too much from those cases. But A gives a different reason for that caution: most new drugs require large studies before being considered effective. That is a requirement about testing, not evidence that most patients given this drug failed to improve.

  To match the original, we would want the many misses alongside the few apparent successes. Merely including the word “most” doesn't supply that structure when it describes a testing requirement instead.

• B

  This has successful and unsuccessful cases, but it does not establish that the unsuccessful cases make up most of the group. Many people could fail to improve while a much larger number benefit. The original's reason for dismissing several matches is that the vast majority of dreams do not match later events. B never gives us that imbalance. Its conclusion resembles the original's skeptical conclusion, but the supporting comparison is different.

• C

  The conclusion rejects a proposed causal connection, which is a promising start. The reason is different, though: several factors are relevant to remission. The researcher didn't reject the inference about dreams by identifying several alternative factors. The researcher pointed to the vast majority of dreams that do not match later events. C lacks that comparison between the apparent confirming cases and the much larger group without the outcome.

• D
  Correct

  Match the roles, not the sentence order. Taking aspirin corresponds to having dreams. Premature death is the outcome that might tempt someone to see a connection, just as a later event matching a dream might tempt someone to believe in extrasensory perception. The people who take aspirin and die prematurely supply the apparent confirming cases.

  The final sentence provides the other side: most aspirin users do not die prematurely. That corresponds to the vast majority of dreams failing to resemble later events. On that basis, D rejects the inference that aspirin is dangerous, just as the original rejects belief in extrasensory perception based solely on several matching dreams.

  Don't reject D after its opening phrase, “A number.” Those are the few apparent matches, not the majority of misses. Both groups are present; the majority statement simply comes last. Nor should we rewrite either conclusion as a proof that no connection could ever exist. Both arguments concern what these cases justify believing.

• E

  This moves toward accepting a connection, whereas the original rejects the inference from several matches. E says that it is unreasonable to deny a link despite the people who never develop cancer; the researcher says that it is unreasonable to believe in the proposed ability given the many dreams that do not match events.

  E also gives us a significant number on one side and many on the other, not a majority without the relevant outcome. Similar subject matter and a mix of cases are not enough when both the conclusion's direction and the supporting proportions differ.