Effect of Heartwood and Sapwood Ratio on Adhesion Strength of Finished Wood Species

Table 2

Statistical analysis of the roughness and adhesion strength test results.

Source	Sum of squares	df	Mean square	value	Significance level
Surface roughness
Effect of heartwood and sapwood (A)	196,28	1	196,28	6,480	NS
Effect of sanding (B)	28402.39	2	14201.19	468.825
Effect of species (C)	2845.37	3	948.46	31.312
A × B	1222.69	2	611.34	20.182
A × C	192.06	3	64.02	2.114	NS
B × C	1693.82	6	282.30	9.320
A × B × C	359.39	6	59.90	1.977	NS
Error	17447.63	576	30.29
Total	956260.10	600
Adhesion strength
Effect of heart and sapwood (A)	0.57	1	0.57	7.70	NS
Effect of sanding (B)	2.82	2	1.41	18.96
Effect of species (C)	15.29	3	5.09	68.46
A × B	1.91	2	0.95	12.84
A × C	0.60	3	0.20	2.72
B × C	0.56	6	0.09	1.26	NS
A × B × C	1.66	6	0.27	3.71
Error	33.95	456	0.07
Total	2250.38	480

NS: nonsignificant. Significant at the α = 0.05 level. Significant at the 0.01 level. Significant at the α = 0.001 level.