Which group is used when the tested variable is applied to compare outcomes against expectations?

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

Answer: (B)

When you apply a tested variable and want a benchmark to show you’re achieving the expected effect, you use a positive control. This group receives a treatment known to produce the anticipated response, so its outcome confirms that the system and measurement can detect the effect you’re looking for. If the positive control behaves as expected, you can trust that differences you see in the experimental group are due to the variable itself rather than a flaw in the assay. In contrast, a negative control shows no effect, and a standard control (no treatment) provides a baseline. The experimental group is the one where the variable is actually applied, not the benchmark.