What is a manipulated variable in an experimental research design?

A manipulated variable, also known as an independent variable, is the factor that researchers deliberately change or control in an experimental research design to observe its effect on another variable, known as the dependent variable. By systematically altering the manipulated variable, researchers can establish cause-and-effect relationships and determine how changes influence the outcome of the experiment. This allows for rigorous testing of hypotheses and the evaluation of specific effects in a controlled environment.