Table 9: Statistical analysis of the correlations between the residuals of the index- $\sigma$ relation and the H $\beta$ index. For a significance level lower than $\alpha =0.05$ , a value of t higher than 1.96 confirms the existence of correlation.
LDEG HDEG

Index t t

D4000 1.00 -1.06

H $\delta_A$ 0.08 -0.50

H $\delta_F$ 2.50 0.73

CN₂ -0.85 0.42

Ca4227 0.34 0.36

G4300 2.21 1.04

H $\gamma_A$ -0.29 -0.34

H $\gamma_F$ 2.07 -0.04

Fe4383 3.00 0.82

Fe4531 2.61 0.90

Ca4455 2.93 0.56

C4668 1.47 0.16

Fe5015 1.32 2.23

Mgb -4.24 0.36

Fe5270 1.97 1.50

Fe5335 2.20 1.85

**Table 9:** Statistical analysis of the correlations between the residuals of the index- $\sigma$ relation and the H $\beta$ index. For a significance level lower than $\alpha =0.05$ , a value of t higher than 1.96 confirms the existence of correlation.
	LDEG	HDEG
Index	t	t
D4000	1.00	-1.06
H $\delta_A$	0.08	-0.50
H $\delta_F$	2.50	0.73
CN₂	-0.85	0.42
Ca4227	0.34	0.36
G4300	2.21	1.04
H $\gamma_A$	-0.29	-0.34
H $\gamma_F$	2.07	-0.04
Fe4383	3.00	0.82
Fe4531	2.61	0.90
Ca4455	2.93	0.56
C4668	1.47	0.16
Fe5015	1.32	2.23
Mgb	-4.24	0.36
Fe5270	1.97	1.50
Fe5335	2.20	1.85

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