Stat > DOE > Factorial > Create Factorial Design > Factors
Complete the following steps to specify details about the factors in the design.
Under Name, enter a descriptive name for each factor. By default, Minitab names the factors alphabetically, skipping the letter I.
For each factor, specify whether the factor is text or numeric. If your design includes center points and you enter a combination of text and numeric factors, then Minitab adds a center point at each level of the text factor and the midway level of the numeric factors. For more information, go to How Minitab adds center points to a two-level factorial design.
Enter the high and low levels for each factor. For example, an engineer wants to test two different temperatures and enters 150 for low and 250 for high. By default, Minitab sets the low level of all factors to −1 and the high level to +1 in coded units. If you have a text factor and the levels have no natural order, you can specify either level as low or high.