What type of variable is manipulated by the researcher in a graph?

The variable that a researcher manipulates in an experiment is known as the independent variable. This is the factor that is changed or controlled to test its effects on other variables, allowing researchers to observe how changes in this variable influence outcomes.

For example, if a study is examining the impact of different amounts of sunlight on plant growth, the amount of sunlight received would be the independent variable because it is what the researcher alters to see how it affects the plants. By isolating this variable, the researcher can determine whether variations in sunlight lead to significant differences in plant growth, thus establishing a cause-and-effect relationship.

Additionally, the dependent variable is the outcome that is measured in response to changes in the independent variable, while controlled variables are factors that are kept constant to ensure that the test results are valid. Random variables typically refer to elements that may vary in an unpredictable manner, which are not purposely manipulated by the researcher. Understanding the distinction between these types of variables is crucial for designing experiments and interpreting their results accurately.