In science, variables are any characteristics that can take on different values, such as height, age, temperature, or test scores. There are two types of variables: independent and dependent.
A dependent variable is what you measure in an experiment and what is affected during the experiment. It responds to the independent variable and is called dependent because it "depends" on the independent variable. In other words, it is the variable that changes as a result of the independent variable manipulation. The dependent variable is the outcome youre interested in measuring.
For example, if you are interested in how stress affects heart rate in humans, your independent variable would be the stress and the dependent variable would be the heart rate. You can directly manipulate stress levels in your human subjects and measure how those stress levels change heart rate.
In summary, a dependent variable is the variable that is being tested in a scientific experiment. It is what you measure and it “depends” on your independent variable.
