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 signifi-
cance 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.