Which variable's value is affected by changes in the independent variable?

The dependent variable is defined as the variable that is observed or measured in an experiment. Its value is directly influenced by changes in the independent variable, which is the variable that is manipulated by the researcher to observe the effects of that manipulation. For example, if a researcher is studying the effect of different amounts of sunlight on plant growth (where sunlight is the independent variable), the growth of the plants (the dependent variable) will vary based on the amount of sunlight received.

In contrast, the independent variable stands on its own and is not affected by other variables in the context of the experimental setup. Control variables are conditions that are kept constant to ensure that the test is fair, preventing them from influencing the dependent variable. Extraneous variables are any other variables that could affect the outcome of the experiment but are not the focus of the study, and their effects are generally undesirable as they can introduce noise into the results. Thus, the dependent variable is the key outcome that researchers analyze to see how it is influenced by alterations in the independent variable.