Table 4.

Statistical evaluation between test and placebo groups prior to clinical trial.

Parameter	Site	Levene’s test for equality of variances		t-test for equality of means
		F	Sig	t	df	Sig.a	Mean dif	Std. dif
Hydration	Eye	1.067	0.306	− 0.115	54.719	0.909	− 0.33667	2.93404
	Cheek	0.470	0.496	0.563	57.284	0.576	1.61333	2.86715
Elasticity	Eye	0.006	0.936	1.233	57.564	0.223	0.015800	0.012814
	Cheek	0.050	0.824	− 0.305	57.393	0.762	− 0.002617	0.008585
Skin wrinkle (Eye corner)	Surface	1.111	0.296	− 1.077	57.719	0.286	− 9.61800	8.93090
	Volume	0.789	0.378	0.527	51.309	0.601	2.85556	5.42044
	Ra	0.179	0.674	− 0.931	57.742	0.356	− 1.11111	1.19328
	Rz	1.723	0.194	− 0.919	55.160	0.362	− 0.25556	0.27805
Skin wrinkle (Cheek)	Surface	1.388	0.244	− 0.322	54.856	0.749	− 3.67633	11.43289
	Volume	4.553	0.037	1.634	48.524	0.109	5.91167	3.61784
	Ra	3.109	0.083	0.258	55.425	0.798	0.40000	1.55178
	Rz	1.134	0.291	0.701	55.533	0.487	0.27778	0.39654

^ap > 0.05 indicating non-significant differences between test and placebo groups at baseline evaluated by independent t-test.

Mean dif. : Mean difference; Std. dif. : Standard error difference.