Multiple linear regression analysis is used when there are several independent interval level variables. For example, a linear equation could be derived which related income to years of education, age and years of job experience.
In many situations the researcher does not know which, or how many, independent variables will provide a satisfactory model. There is a choice of methods for adding more independent variables to the model. See also CORRELATION, ANALYSIS OF VARIANCE, CAUSAL MODELLING, PATH ANALYSIS.