What is the difference between independent and dependent variables?

What is the difference between independent and dependent variables?

• A. Independent variables are manipulated, while dependent variables are measured.
• B. Independent variables are measured, while dependent variables are manipulated.
• C. Both are measured.
• D. There is no difference.

Answer: (A)

In experiments, you distinguish between what you manipulate and what you observe. The variable you deliberately change is the independent variable. It’s the input or treatment you control to test its effect. The variable you measure in response is the dependent variable; it reflects the outcome and depends on the level of the independent variable. For example, if you vary the amount of fertilizer (independent) and measure plant height after a set period (dependent), you’re examining how the treatment influences growth. Other factors are kept constant to avoid confounding effects. This is why the statement that independent variables are manipulated while dependent variables are measured is correct. The other options mix up the roles—measuring the independent variable or manipulating the dependent variable, or claiming both are measured or that there’s no difference—don’t describe how experiments reveal cause-and-effect relationships.

In experiments, you distinguish between what you manipulate and what you observe. The variable you deliberately change is the independent variable. It’s the input or treatment you control to test its effect. The variable you measure in response is the dependent variable; it reflects the outcome and depends on the level of the independent variable. For example, if you vary the amount of fertilizer (independent) and measure plant height after a set period (dependent), you’re examining how the treatment influences growth. Other factors are kept constant to avoid confounding effects. This is why the statement that independent variables are manipulated while dependent variables are measured is correct. The other options mix up the roles—measuring the independent variable or manipulating the dependent variable, or claiming both are measured or that there’s no difference—don’t describe how experiments reveal cause-and-effect relationships.