Table 3. Analysis of variance of regression coefficient calculated for gelatin extraction from Korean native black goat skin

Independent variable	Extraction yield (%)		Gel strength (g)
	Regression coefficient	p-value	Regression coefficient	p-value
Constant	12.561	<0.001	263.14	<0.001
Linear
X1	1.777	<0.001	–6.10	0.002
X2	0.501	0.004	–2.34	0.110
Quadratic
X12	–0.697	0.005	0.55	0.780
X22	0.036	0.845	–4.65	0.043
Interaction
X1X2	–0.117	0.450	–1.59	0.346

X₁, extraction temperature (°C); X₂, extraction time (h).