The dependent or response variable is the variable whose behaviour is to be measured as a result of an experiment. For example, in a consumer research study on the effects of types of packaging on purchase behavior (where the size, shape and colors of the box are the independent variables), the dependent variable would be the quantity of product purchased.
Ideally, the dependent variable should be reliable, sensitive, easy to measure, and distributed in a way that conforms to the assumptions of a statistical model.
By convention, the dependent variable is plotted along the vertical Y-axis with the independent variable on the horizontal X-axis.
Example: in an experiment where the vapor pressure of a liquid is measured at several different temperatures, temperature is the independent variable and vapor pressure is the dependent variable.