Which of the following best defines an independent variable?

The independent variable is best defined as the factor that is manipulated to observe effects. In experimental research, the independent variable is the condition or factor that researchers deliberately change or control to investigate its impact on another variable, known as the dependent variable. By altering the independent variable, researchers can measure how it affects the outcome of the experiment, allowing them to establish causal relationships between variables.

For example, if a study is examining the effect of different amounts of sunlight on plant growth, the amount of sunlight would be the independent variable, as it is the condition being changed. The growth of the plants would then be measured as the dependent variable, providing insight into how variations in the independent variable influence the outcome. This manipulation is crucial in experimental designs as it helps to isolate the effects of the independent variable and establishes a clearer picture of the cause-and-effect relationship.