can be viewed as a variation of the forward selection
method since predictor variables are entered ontime, but true stepwise entry differs from forward
entry in that at each step of a stepwise analysis the
removal of each entered predictor is also considered;
entered predictors are deleted in subsequent steps if
they no longer contribute appreciable unique
predictive power to the regression when considered in
combination with newly entered predictors (Thompson,
1989). (p. 99)e at a