An independent variable is a variable that stands alone and is not influenced by any other variables in the study. It is the variable that is manipulated or varied in an experimental study to explore its effects. In other words, it is the variable that is being tested to see how it affects the dependent variable. Some examples of independent variables include time, space, density, mass, fluid flow rate, and previous values of some observed value of interest. Independent variables are also called explanatory variables or predictor variables. In contrast, a dependent variable is something that depends on other factors. It is the variable whose variation is being studied, by altering inputs. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before, etc. .