Consider the experiment in Exercise 7-4. Suppose that the experiment was actually carried out on three levels of temperature and two positions. The data are the following:
(a) Perform the analysis of variance with α = 0.05. What is your conclusion about the significance of the interaction effect?
(b) Assess the adequacy of the model by analyzing the residuals. What is your conclusion?
(c) If higher density values are desirable, what levels of the factors do you recommend?