Indicates forward regression. An attempt is made to add a variable to the model. A variable is added if its p-value is less than PValueIn. During intitialization, only forced variables enter the model.

Indicates backward regression. An attempt is made to remove a variable from the model. A variable is removed if its p-value exceeds PValueOut. During initialization, all candidate independent variables enter the model.

Indicates stepwise regression. A backward step is attempted. After the backward step, a forward step is attempted. This is a stepwise step. Any forced variables enter the model during initialization.