A two-way ANOVA was carried out to assess the impact of type of farm (government agricultural settlement, established, individual) and tractor maintenance method (preventive, predictive, running, corrective, overhauling, breakdown) on the response variable maintenance practice contribution. There were two observations for each combination of factor levels. The resulting sums of squares were SSA = 35.75 (A = type of farm), SSB = 861.20, SSAB = 603.51, and SSE = 341.82 ("Appraisal of Farm Practice Maintenance and Costs in Nigeria," J. of Quality in Maintenance Engr., 2005: 152-168). Assuming both factor effects to be fixed, construct an ANOVA table, test for the presence of interaction, and then test for the presence of main effects for each factor (all using level .01).