A sensitivity analysis based on block plots was performed [28-30]. Block plots assess whether the factor of interest (known as the target factor) has a statistically significant effect on the decreasing mean modulus ratio, and whether that conclusion about the target factor is valid robustly or unconditionally over all other non-target factors (known as robustness factors) in the experiment. The
TABLE 1—ANOVA results.
block plot is essentially a character plot with the boxes superimposed for each setting in order to force attention on the within-box target values, as opposed to the between-box differences. It is an excellent graphics tool for robustly assessing the importance of each individual factor.