Introduction - If you have any usage issues, please Google them yourself
the basic idea is out there Progressive. Specific approach to the introduction of a variable one, every since the introduction of a variable, the right has been elected to the variables for each test, When the original due to the introduction of variable behind the introduction of variable is no longer significant, and should he be removed. Introduction of a variable regression equation or removed a variable, for the gradual return of the step, every step must undergo inspection, to ensure that each introduction of a new variable, before regression equations contain only significant variable. This process repeated until no significant variables into the equation election, are all significant variables from the regression equation far removed.