Die for full veneer crown. Refer to the Journal of International Society of Preventive Community Dentistry (Vol. 10, 2020) for the dimensional accuracy of veneer crowns, Exercise 9.80 (p. 587). Consider the accuracy as a dependent variable and the two impression materials (additional silicone or condensation silicone) and three core materials (fabricated of amalgam, composite resin, or nickel–chromium) as the independent variables. The data (simulated from information provided in the study) are saved in a file.

a. Consider the independent variable, impression. Write a model for mean accuracy as a function of this independent variable. Give a meaningful interpretation of each b in the model.

b. Fit the model in part a to the data and give an assessment of model adequacy.

c. Consider the independent variable, core. Write a model for mean accuracy as a function of this independent variable. Give a meaningful interpretation of each b in the model.

d. Fit the model in part c to the data and give an assessment of model adequacy