Table 3. Total Model Comparisons Performed via Statistical Methodologies where M Indicates HNO₃ Concentration, and T Indicates Temperature.

Tukey–Kramer statistical comparisons	RMSEP % values	statistical significance
PLSR D-Opt (M) vs PLSR 7-L (M)	1.8 vs 1.9	yes
PLSR D-Opt (T) vs PLSR 7-L (T)	6.9 vs 7.3	no
SVR D-Opt (M) vs SVR 7-L (M)	2.1 vs 1.8	no
SVR D-Opt (T) vs SVR 7-L (T)	5.6 vs 2.3	yes
PLSR D-Opt (M) vs SVR D-Opt (M)	1.8 vs 2.1	yes
PLSR D-Opt (M) vs SVR 7-L (M)	1.8 vs 1.8	yes
PLSR 7-L (M) vs SVR D-Opt (M)	1.9 vs 2.1	yes
PLSR 7-L (M) vs SVR 7-L (M)	1.9 vs 1.8	yes
PLSR D-Opt (T) vs SVR D-Opt (T)	6.9 vs 5.6	no
PLSR D-Opt (T) vs SVR 7-L (T)	6.9 vs 2.3	yes
PLSR 7-L (T) vs SVR D-Opt (T)	7.3 vs 5.6	yes
PLSR 7-L (T) vs SVR 7-L (T)	7.3 vs 2.3	yes