A Design of Experiment (DOE) analysis enables you to see the effect of some intervention on the quality of the part. The input variables are the interventions. For example, you can change the melt temperature, or coolant inlet temperature, and see the effect on part quality.
The input variables listed in the DOE Builder are imported from the base study, and change depending upon the process settings you have chosen. When selected in the DOE Builder, these parameters appear in the tree in the 
Optimization tree in theStudy tasks pane. The Variables tree may have as many as three sections, depending on the variables in the study:
Processing conditions
The processing conditions include those variables associated with the actual production of the part. The variables listed will depend on the molding process and analysis sequence selected, and include variables such as filling control, cooling time, curing temperature, injection time, pack/holding control, etc.
Boundary condition variables
Boundary conditions include those variables that define how the heat transfer conditions between the mold and the material are modelled. Boundary conditions include coolant inlet and all the variables associated with the coolant, valve gate timing and all associated variables, the mold surface temperature profile controller, the hot gate pressure controller and the gas inlet controller and all its associated variables.
Geometry variables
Geometry refers to those variables associated with the physical design of the part, such as thickness.
The values you have set in the process settings are imported into the DOE Builder, where they are listed as the Middle Value. The DOE Builder assigns a range around the Middle Value, which you can change to make it wider or narrower. Profile data is also imported into the DOE Builder from the Process Settings. This data can only be changed in the process settings. However, Xmax, Xmin, Ymax and Ymin can all be edited in the DOE Builder.