Table 4. Discriminant coefficient, standardized discriminant coefficient, partial F-value, and P-value for each of the 15 variables selected in the stepwise analysis for the discriminant function to separate faces during smiling and resting postures in the younger group.

Facial characteristics to discriminate rest vs. smile postures in the younger group	Discriminant coefficient	Standardized discriminant coefficient	Partial F-value	P-value	Structure matrix
Increase in facial width at level of the upper lip during smiling (Ls//axial_|E-E|)	-0.28	-2.11	57.65	1E-12	-0.21
Increase in cheek protrusion at level of chin during smiling (Sm//axial_∠E-P-M, right)	0.05	0.24	37.16	6E-9	-0.17
Increase in cheek protrusion in orbital regions during smiling (Ex-Ch//z_|L1-P| (left, % to |L1-L2|)	-0.02	-0.24	35.51	1E-8	-0.17
Increase in facial width at level of base of columella level during smiling (Sn//axial_|E-E|)	0.23	1.67	11.83	7E-4	-0.10
Posterior movement of nasal dorsum during smiling (N//saggital_v7)	-0.18	-0.65	2.86	9E-2	0.05
Retrusive movement of nasal ala during smiling En-Ac//z_∠L1-L2, right)	0.10	0.40	5.97	2E-2	0.07
Upward movement of eyes during smiling (|N-En|)	0.21	0.32	6.43	1E-2	0.07
Decrease in lower lip height during smiling (|Sto-Li|)	0.11	0.21	46.39	1E-10	0.19
Retrusive movement of lower lip during smiling (Li//axial_|M|)	-0.21	-0.36	77.22	7E-16	0.24
Decrease in the lower face height during smiling (|Sn-Gn|/|N-Gn|)	15.73	0.45	78.78	4E-16	0.25
Retrusive movement of upper lip during smiling Prn//saggital_v6 (%;)	-0.05	-0.18	103.92	2E-16	0.28
Decrease in the protrusion of the cheek at level of lower lip during smiling (Li//axial_|P|, right)	0.32	0.47	174.71	2E-16	0.37
Decrease in the labio-mental fold during smiling (Prn//saggital_v11)	0.18	0.57	192.49	2E-16	0.38
Retrusive movement of lip commissure relative to nasal ala during smiling (Ac-Ch//z_∠L1-L2, right)	0.09	0.54	378.42	2E-16	0.54
Constant	-3.01