Analysis of variance is a method of portioning variability into identifiable sources of variation and the associated degree of freedom in an experiment. The frequency test (F-test) is
utilized in statistics to analyze the significant effects of the parameters, which form the quality characteristics. Table 3 shows the result of ANOVA analysis of S/N ratio for surface
roughness. This analysis was carried out for a level of significance of 5%, i.e., for 95% a level of confidence. The last column of the table shows the “percent” contribution (P) of each factor as the total variation, indicating its influence on the result. From the analysis of Table 3 it is apparent that, the F-values of cutting speed, feed rate and depth of cut were all greater than F0.05,2.26 = 3.146 and have statistical, physical significance on the surface roughness.