Table 5.

Linear regression models for the effects of group, age and gender over IGFBP-7 levels.

Predictors	F (df1, df2)	R2	p	β	SD	pβ
Model 1	9.37 (3, 95)	0.23	<0.001	31.18	9.29	0.001
Group				7.21	5.26	0.174
Age				0.76	0.19	<0.001
Gender				7.92	4.93	0.112
Model 2	13.00 (2, 96)	0.21	<0.001	29.61	9.26	0.002
Age				0.85	0.17	<0.001
Gender				9.13	4.88	0.064

Linear regression models were performed using the backpropagation method, excluding variables from the model that do not have a significant impact on the variance explained. Df1: degrees of freedom of the independent variables. df2: degrees of freedom of the dependent variable. R²: R-squared. p: p-value of the regression equation of each model. β: beta coefficients. SD: Standard deviation of beta coefficients; p^β = p-value of the beta coefficients. Group is a dichotomic variable formed from mental condition (healthy, depression). Age is a continuous variable. Gender is a dichotomic variable formed from sex (male, female). We show exact p-values for the better understanding of the models.