Table 6: Results of ANOVA.

Source DF SS MS % contribution A 2 10.005 5.002 1.81* 13.8 B 2 1.328 0.664 0.24 1.8 C 2 1.763 0.881 0.32 2.5 D 2 3.523 1.761 0.64 4.9 A * B 4 18.481 4.62 1.67 25.6 A * C 4 12.938 3.235 1.17 17.9 B * C 4 7.619 1.905 0.69 10.5 Error 6 16.57 2.762   23 Total 26 72.227

*Significant at 75% confidence level .