When Testing a New Drug for an Illness, Which of These

Multiple Choice

When testing a new drug for an illness, which of these is a major reason to use a control group?

A) Control groups eliminate all other factors that may cause statistical noise.
B) More than one group is required to perform a statistical test for differences between a response and an expected response.
C) People often get better just from thinking they have been treated, regardless of the actual effectiveness of the drug.
D) Statistical power is maximized in tests that use two groups compared to those that just use one.