To Assess the Effectiveness of Flu Vaccine for County Residents,Mr

Multiple Choice

To assess the effectiveness of flu vaccine for county residents,Mr.McCallum wants to administer vaccine injections to all county residents rather than give half of them a placebo injection.Mr.McCallum is most clearly underestimating the importance of

A) testing a large sample.
B) operationally defining his procedures.
C) replicating observations of other researchers.
D) creating a control group.