Specify the terms to use in your model. Minitab includes a set of terms based on the order of the model that you specify, or you can choose the terms directly from the list of all available terms. For more information about terms and the model order, go to Models, the terms that they fit, and the type of blending that they model.
If you choose a stepwise procedure in the main dialog box, the terms you specify are candidates for the final model. Click the Options
button to modify the selection criteria for the stepwise procedure.
- Include component terms for model
- Select the order of the model for the components. When you select an order, the terms listed in Selected Terms change to reflect your choice.
- Include inverse component terms
- You can fit inverse terms when no components have a lower bound of zero and you choose to analyze the design in proportions. Inverse terms allow you to model extreme changes in the response as the proportion of one or more components nears its lower boundary. Suppose you are formulating lemonade and you are interested in the acceptance rating for flavor. An extreme change in the acceptance of lemonade occurs when the proportion of sweetener approaches zero. That is, the flavor becomes too sour.
- Include process variable terms up through
order or Include
mixture amount terms up through order
- The label of this item changes depending on the whether you have process variables or amount variables in your design. Select an order for all process variables or the amount variable to include in the model. When you select an order, the terms listed in Selected Terms change to reflect your choice.
- Available Terms
- Lists all of the terms that you can add to the model.
- Selected Terms
- Lists all of the terms that will be included in the model. Use the arrow buttons to move Available Terms to Selected Terms.
- Use the arrow buttons to move Available Terms to Selected Terms. Select one or more terms in one of the lists, then click an arrow key. The double arrows move all the terms in one list to the other. You can also move a term by double-clicking it.
- Include blocks in the model
- Select to include blocks in the model. Minitab enables the checkbox if multiple values are in the block column for the design.
- Blocks account for the difference that might occur between runs that are performed under different conditions. For more information, go to What is a block?.