To indicate the statistical significance of each variable on the response factor, Figure 2 shows the variation of COD removal due to changes in the level of each factor whose importance for the process is related to the slope of the corresponding line.
To indicate the statisticalsignificance of each variable on the response factor, Figure 2shows the variation of COD removal due to changes in the levelof each factor whose importance for the process is related tothe slope of the corresponding line.