D. Radson et Gd. Herrin, AUGMENTING A FACTORIAL EXPERIMENT WHEN ONE FACTOR IS AN UNCONTROLLABLE RANDOM VARIABLE - A CASE-STUDY, Technometrics, 37(1), 1995, pp. 70-81
Process engineers at an automobile assembly plant wanted to develop a
model for on-line process control in an assembly line. During an exper
iment to estimate the model, an uncontrollable variable was discovered
to have a significant effect, but its values in the experiment were n
ot representative of values in actual production. Through this case st
udy, we present design criteria and assess sampling strategies for aug
menting a factorial experiment to incorporate an additional factor tha
t was found to be an uncontrollable independent normally distributed r
andom variable. Our results demonstrate the potential improvement in o
n-line process control when experiments are augmented using these desi
gn criteria.