Why Did the Pretesting of Negative Advertisements Against Jean Chretien

Multiple Choice

Why did the pretesting of negative advertisements against Jean Chretien during the 1993 election fail to generalize to the actual public reaction according to your text?

A) The sample may not have been representative of the general public.
B) The researchers used correlation in opinion polling instead of experimentation.
C) A confounding variable was inadvertently introduced because they showed Mr. Chretien's facial paralysis.
D) The double-blind procedure should have been used.
E) A single-blind procedure should have been used.