Which is correct and most complete?

a. Using FF, once an array is chosen, generally only the first m columns are used.

b. Typically roughly half of the settings change from run to run in applying FF.

c. Selecting the factors and levels is critical and should be done carefully.

d. Main effects plots often clarify which factors matter and which do not.

e. The approved approach for designing systems is to select the DOE array settings that gave the best seeming responses.

f. All of the above are correct.

g. All of the above are correct except

(e) and (f).