larger or smaller of the 2 sets is retained-whichever set has the first discarded variable is the one which can end up discarded in the entirety. One property thus of the stepdown procedure is that it discards only variables which one can afford to discard without seriously impairing the goodness of fit.

Why do we use stepwise regression?

Stepwise regression is an appropriate analysis when you have many variables and you're interested in identifying a useful subset of the predictors. In Minitab, the standard stepwise regression procedure both adds and removes predictors one at a time.

How does the approach stepwise work in the sense of selecting variables?

As the name stepwise regression suggests, this procedure selects variables in a step-by-step manner. The procedure adds or removes independent variables one at a time using the variable's statistical significance. Stepwise either adds the most significant variable or removes the least significant variable.