Table 3.

Regression equation and determination coefficients for response surface regression of the sun protection factor (Y1), antioxidant activity (Y2), critical wavelength (Y3), UVA transmittance (Y4), UVB transmittance (Y5), and UVA/UVB ratio (Y6) as functions of the concentration of sunscreen filters (X1), concentration of extract (X2), and time of irradiation (X3).

Regression Equation	1 R2	2 R2adj	3 R2pred
ln(Y1) = 0.341 + 0.2817 × X1 + 0.1258 × X2 − 0.857 × X3 − 0.01409 × X1 × X1 − 0.00579 × X2 × X2 + 0.1795 × X3 × X3	0.9522	0.9354	0.8849
Y2 = 24.35 − 1.017 × X1 + 3.631 × X2 − 0.1831 × X2 × X2 + 0.0861 × X1 × X2	0.9907	0.9783	0.8295
Y3 = 328.35 + 16.112 × X1 + 0.722 × X2 − 4.91 × X3 − 0.9844 × X1 × X1 − 0.1092 × X1 × X2 + 0.477 × X2 × X3	0.9796	0.9723	0.9361
Y4 = 96.51 − 12.11 × X1 − 4.31 × X2 + 20.96 × X3 + 0.617 × X1 × X1 + 0.285 × X2 × X2 − 4.39 × X3 × X3	0.9401	0.9190	0.8581
Y5 = 68.08 − 12.19 × X1 − 3.41 × X2 + 21.78 × X3 + 0.691 × X1 × X1 + 0.238 × X2 × X2 − 3.91 × X3 × X3 − 0.808 × X2 × X3	0.9495	0.9275	0.8681
Y6 = 0.1409 + 0.1159 × X1 − 0.0559 × X3 − 0.006207 × X1 × X1	0.9459	0.9378	0.9082

¹ Coefficient of determination; ² Adjusted coefficient of determination; ³ Predicted coefficient of determination.