Problem 13.6 Two types of fertilizer are being compared against a control (no fertilizer). The response variable is the yield (tons) in sugar beets. The results are displayed in the next table.

(a) Calculate the ANOVA table and test whether there are differences among the treatments. Use α = 0.05.

(b) Check the model assumptions. Fertilizer Applied None P O4 P O4 N03 Area 1 12.45 6.71 6.48 2 2.25 5.44 7.11 3 4.38 4.92 5.88 4 4.35 5.23 7.54 5 3.42 6.74 6.61 6 3.27 4.74 8.86