Data Analysis

One approach to examining the results is the use of 3D graphs such as that shown in Fig. 6, which plots the apparent modulus ratio against the tempera­ture and the maximum strain in the cyclic movement during 1 month of expo­sure at 75 % RH with UV radiation. The graph shows that both motion and temperature produce a significant reduction in the modulus for the range of conditions tested. Moreover, the effects are synergistic in that the combination of motion and temperature produced a larger reduction in modulus than that seen for either variable alone.

This approach is useful for illustrating general trends and highlighting the nature of the response surface. However, as the goal of this paper is to identify and rank environmental factors that are important to sealant degradation, we take a different approach to the data analysis. More specifically, design of experiments (dex) scatter plots, dex mean plots, analysis of variance (ANOVA), and block plots [28] are used. Of all of these statistical techniques, the block plot bears the most weight.