Property Optimisation of EPDM Rubber Composites Using Mathematical and Statistical Strategies

Table 5

Major statistical properties [7, 8] relevant for variance analysis (R², value for the significance and lack-of-fit tests) of the calculated regression models (X₁ calcium carbonate, X₂ paraffinic oil, and X₃ vulcanising accelerator).

Effect	value
	HD	TS	EB	RS
X1	—	0.00	0.00	0.00
X1^2	—	0.07	—	0.07
X2	0.00	—	0.00	—
X2^2	—	0.00	0.13	0.00
X3	0.06	0.10	0.12	0.10
X3^2	—	0.20	—	0.20
X1X2	—	0.27	—	0.27
X1X2^2	0.03	0.26	0.09	0.25
R^2	0.85	0.82	0.96	0.96
Lack-of-fit	0.99	0.89	0.77	0.55

values of the effects used in the regression models. Other insignificant values (>0.10) are not presented.