PrepTest 128, Section 1, Question 28

Working the answers

• A

  The failure happens despite starting conditions that are “in fact exactly the same.” That's a different problem. Sommerer and Ott's model involves small differences in starting conditions producing radically different results.

• B
  Correct

  Here the scientist can't recreate the starting conditions exactly and therefore can't consistently recreate the reaction. That fits the proposed explanation of failed replication: tiny differences that can't be eliminated may matter enormously to the outcome.

• C

  This scientist can't even make the starting conditions approximately the same. Of course a substantially different experiment might yield a different result. The striking feature of the model is that a tiny, even undetectable difference can be enough. C doesn't isolate that feature.

• D

  The scientist can consistently reproduce the reaction even with substantially different starting conditions. That shows a stable result despite changed conditions—the opposite of the replication problem we're trying to illustrate.

• E

  The timing changes, but the scientist can still consistently reproduce the reaction. The example doesn't show an inability to replicate the result because of tiny differences in starting conditions.