逐步回归的基本思想是有进有出。具体做法是将变量一个一个引入，当每引入一个自变量后，对已选入的变量要进行逐个检验，当原引入的变量由于后面变量的引入而变得不再显著时，要将其剔除。引入一个变量或从回归方程中剔除一个变量，为逐步回归的一步，每一步都要进行 检验，以确保每次引入新的变量，之前回归方程中只包含显著的变量。这个过程反复进行，直到既无显著的自变量选入回归方程，也无不显著自变量从回归方程中剔除为止。-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.