In a controlled scientific experiment, which variable is deliberately changed by the experimenter?

In a controlled scientific experiment, which variable is deliberately changed by the experimenter?

• A. Dependent variable
• B. Control variable
• C. Constant variable
• D. Independent variable

Answer: (D)

The variable you deliberately change to see its effect is the independent variable. It’s the factor the researcher manipulates to test what happens under different conditions. The outcome you measure, which shows how the change influences results, is the dependent variable. To make sure any observed effect comes from the manipulation and not other factors, you keep all other conditions the same as control variables. For example, if you study how sunlight affects plant growth, the amount of sunlight is the independent variable, the plant height you measure is the dependent variable, and you keep water, soil, and temperature constant as control variables. This setup lets you attribute changes in the dependent variable to the independent variable.

The variable you deliberately change to see its effect is the independent variable. It’s the factor the researcher manipulates to test what happens under different conditions. The outcome you measure, which shows how the change influences results, is the dependent variable. To make sure any observed effect comes from the manipulation and not other factors, you keep all other conditions the same as control variables. For example, if you study how sunlight affects plant growth, the amount of sunlight is the independent variable, the plant height you measure is the dependent variable, and you keep water, soil, and temperature constant as control variables. This setup lets you attribute changes in the dependent variable to the independent variable.