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What
can you conclude from these data?
You answered:
 The
result is inconclusive. One possibility is that Drug X is
ineffective in this condition. An alternative possibility
is that although Drug X would usually be effective in this
condition, the methods of this particular study were flawed
and therefore the study lacked "assay sensitivity."
CORRECT
A
finding of "no significant differences" is equivocal
in a symptom study. The absence of a difference may reflect
that the drug is truly ineffective or alternatively, that
the study lacked sensitivity to demonstrate an effect.
Even
if Drug X is truly analgesic, the assay may have been insensitive
because patients had pain too severe to respond to the analgesic,
the pain questionnaires were confusing, or the procedures
of the nurse-observer inconstant. A final possibility is
that the finding of no difference may have been a false
negative due to random variation.
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