
251Factorial Design of Experiments to Optimize a Chemical Process
box shown in Figure14.33 reappears. Click on “OK” and the plots shown in
Figures14.37 and 14.38 are produced.
Figure14.37 is the main effects plot for Cost with respect to Time, Temp, and
Catalyst. Notice that Time of 20 minutes is better than 50 minutes, because
the average Cost is lower for the former. Also, Temp of 150 Fahrenheit is
better than 200 Fahrenheit, because the average Cost is lower for the former.
Finally, Catalyst Ajuba is better than Catalyst Tapori, because the average
Cost is lower for the former.
Figure14.38 is the interaction plot for Cost with respect to ...