What is the difference between independent and dependent variables?

What is the difference between independent and dependent variables?

• A. Independent variables are manipulated by the experimenter, while dependent variables are measured and expected to be influenced by the independent variable.
• B. Independent variables are measured, dependent variables are manipulated.
• C. Both are manipulated by the experimenter.
• D. They are the same concept.

Answer: (A)

In experiments, the variable you actively change is the independent variable, and the variable you observe or measure to see the effect is the dependent variable. The independent variable is under the researcher’s control, while the dependent variable is the outcome you expect to be influenced by that manipulation. For example, if you want to know whether sleep duration affects test performance, the hours of sleep you assign to participants is the independent variable, and the test score you measure afterward is the dependent variable. You’d aim to keep other factors constant so that any change in test scores can be linked to differences in sleep. This description best captures the distinction. The idea that the independent variable is measured and the dependent variable is manipulated, or that both are manipulated, or that they are the same concept, doesn’t fit how experiments are designed because it confuses which factor you change versus which factor you observe.

In experiments, the variable you actively change is the independent variable, and the variable you observe or measure to see the effect is the dependent variable. The independent variable is under the researcher’s control, while the dependent variable is the outcome you expect to be influenced by that manipulation.

For example, if you want to know whether sleep duration affects test performance, the hours of sleep you assign to participants is the independent variable, and the test score you measure afterward is the dependent variable. You’d aim to keep other factors constant so that any change in test scores can be linked to differences in sleep.

This description best captures the distinction. The idea that the independent variable is measured and the dependent variable is manipulated, or that both are manipulated, or that they are the same concept, doesn’t fit how experiments are designed because it confuses which factor you change versus which factor you observe.