Referring to Problem 11.36, the effect of die temperature and die diameter on the foam diameter was also measured and the results stored in PackagaingFoam2.

An experiment was conducted to study the extrusion process of biodegradable packaging foam. Two of the factors considered for their effect on the unit density (mg/ml) were the die temperature (145° C vs. 155° C) and the die diameter (3 mm vs. 4 mm). The results are stored in PackagingFoam1 . (Data extracted from W. Y. Koh, K. M. Eskridge, and M. A. Hanna, “Supersaturated Split-Plot Designs,” Journal of Quality Technology, 45, January 2013, pp. 61–72.)

At the 0.05 level of significance,

a. is there an interaction between die temperature and die diameter?

b. is there an effect due to die temperature?

c. is there an effect due to die diameter?

d. Plot the mean foam diameter for each die temperature and die diameter.

e. What conclusions can you reach concerning the importance of each of these two factors on the foam diameter?