4. In an experiment to see whether the amount of coverage of light-blue interior latex paint depends either on the brand of paint or on the brand of roller used, 1 gallon of each of four brands of paint was applied using each of three brands of roller, resulting in the following data (number of square feet covered).

Roller Brand 1 23 1 454 446 451 Paint 2 446 444 447 Brand 3 439 442 444 4 444 437 443

a. Construct the ANOVA table. [Hint: The computations can be expedited by subtracting 400 (or any other convenient number) from each observation. This does not affect the final results.]

b. State and test hypotheses appropriate for deciding whether paint brand has any effect on coverage. Use 
.05.

c. Repeat part

(b) for brand of roller.

d. Use Tukey’s method to identify significant differences among brands. Is there one brand that seems clearly preferable to the others?