Which group is used to establish a baseline by having no variable applied?

• A. Positive control group
• B. Negative control group
• C. Experimental group
• D. Control group

Answer: (B)

Establishing a baseline requires a condition where no variable is applied, which is the role of a negative control. This group is treated identically to the experimental setup except for the absence of the variable being tested, so any observed signal or response reflects background levels, contamination, or other non-specific effects. By comparing the experimental group to this baseline, you can determine whether the variable truly causes the change you’re investigating. The positive control demonstrates a known expected effect to confirm the system can respond; the experimental group tests the variable’s effect; and a general control group is a broader term that may or may not exclude the variable, but it’s the specific “no variable applied” setup that defines a negative control.