hard · LSAT Logical Reasoning

Researcher: Patients given the new analgesic reported greater pain relief, on average, than those given the standard drug. Some have suggested this is merely a placebo effect, since the new drug's distinctive tablet shape may have led patients to expect a stronger effect. But in our trial, neither patients nor the staff administering the tablets knew which patients received which drug, and the two tablets were made visually identical. Which one of the following, if true, most weakens the researcher's response to the placebo-effect suggestion?

1. The new analgesic produces a mild but noticeable tingling sensation shortly after ingestion that the standard drug does not produce.
2. Patients who report greater pain relief in trials are, in general, somewhat more likely to have been assigned to receive an active drug rather than an inert placebo.
3. Some patients in the trial had previously taken the standard drug and recognized its effects, though none had previously taken the new analgesic.
4. The staff who recorded patients' pain reports were different from the staff who administered the tablets and were aware of the trial's purpose.
5. The pain-relief reports were collected several hours after the tablets were administered, by which time the drugs' effects had largely worn off.

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