In an experiment, what is the role of the independent variable?

In an experiment, what is the role of the independent variable?

• A. The variable kept constant
• B. The variable measured
• C. The variable intentionally changed by the researcher
• D. Both measured and changed

Answer: (C)

The key idea is that the independent variable is the factor you deliberately change to test its effect on the outcome. In an experiment, you set or vary this variable on purpose to see how it influences what you measure. For example, if you’re investigating how the amount of sunlight affects plant growth, the amount of sunlight is the independent variable because you control and adjust it to observe changes in growth. The thing you measure—the plant’s growth—is the dependent variable, because it depends on the sunlight you provided. The other roles are different: a variable kept constant is a control variable, which you hold steady so it doesn’t influence the results. The variable that is measured is the dependent variable, not the one you change. So, the independent variable is specifically the factor you change intentionally to test its impact.

The key idea is that the independent variable is the factor you deliberately change to test its effect on the outcome. In an experiment, you set or vary this variable on purpose to see how it influences what you measure. For example, if you’re investigating how the amount of sunlight affects plant growth, the amount of sunlight is the independent variable because you control and adjust it to observe changes in growth. The thing you measure—the plant’s growth—is the dependent variable, because it depends on the sunlight you provided.

The other roles are different: a variable kept constant is a control variable, which you hold steady so it doesn’t influence the results. The variable that is measured is the dependent variable, not the one you change. So, the independent variable is specifically the factor you change intentionally to test its impact.