什麼是控制組？

A control group is a fundamental component of experimental design, serving as a baseline for comparison. It is kept separate from the experimental group, which receives the treatment or intervention being tested. This separation ensures that any observed effects in the experimental group can be attributed to the treatment itself, rather than other confounding variables. While the control group is part of the overall study, it does not receive the specific manipulation being investigated. The options stating that the control group is "still included in the test" or "a part" of the experiment are misleading because they blur the critical distinction between the control and experimental conditions. The core purpose of a control group is to isolate the effect of the independent variable by providing a comparison point that is not exposed to it.