When it is assumed that the values of one variable are a function of others, the variables that can be manipulated to cause a change in the other are called independent or predictor variables. When graphed, the independent or predictor variable are placed on the horizontal axis. EX: The longevity of a restoration (dependent variable) is assumed to depend on properties of the materials used (independent variable). DMF (predicted variable) is assumed to be dependent on age (predictor variable). [See dependent variable