Problem 13.17 The data in the table below come from an experiment to determine the amount of warping (the response variable) in a metal plate as a function of the following two factors: (A) temperature (measured in degrees Celsius), and (B) copper content (mea[1]sured as a percentage).

(a) Compute the estimated cell means and display your results in the format of Table 13.9.

(b) Plot the estimated cell means (i, yij.)(i = 1,..., 4) for each concentration of copper in the format of Figure 13.8. Does the graph support or refute the assumption that there are no interactions between the temperature and copper content of the metal plate?

(c) Test for the existence of interactions and main effects by computing the two-way ANOVA table.

Copper Content (%) (B) Temperature (oC) (A) 40 60 80 100 50 17 20 16 21 24 22 28 27 75 12 9 18 13 17 12 27 31 100 16 12 18 21 25 23 30 23 125 21 17 23 21 23 22 29 31