Table 5 GMM parameters for standardized 2 PCs for data of FTIR spectra.

Mean

μ₁ = [0.35639494, 1.2868471]

μ₂ = [1.85262144, − 1.17630937]

μ₃ = [− 0.793783, 0.07979547]

μ₄ = [0.61405915, − 0.84843964]

μ₅ = [− 1.76857353 − 1.22674042]

Weights

π₁ = 0.3

π₂ = 0.1

π₃ = 0.3

π₄ = 0.2

π₅ = 0.1

Covariance matrices

\(\Sigma_{1} = \left[ {\begin{array}{*{20}l} {7.19461004 \times 10^{ - 3} } \hfill & { - 1.97590685 \times 10^{ - 2} } \hfill \\ { - 1.97590685 \times 10^{ - 2} } \hfill & {5.48141678 \times 10^{ - 2} } \hfill \\ \end{array} } \right]\)

\(\Sigma_{2} = \left[ {\begin{array}{*{20}l} {1.0 \times 10^{ - 6} } \hfill & { - 1.12412679 \times 10^{ - 29} } \hfill \\ { - 1.12412679 \times 10^{ - 29} } \hfill & {1.0 \times 10^{ - 6} } \hfill \\ \end{array} } \right]\)

\(\Sigma_{3} = \left[ {\begin{array}{*{20}l} {1.07131702 \times 10^{ - 1} } \hfill & { - 6.63095448 \times 10^{ - 2} } \hfill \\ { - 6.63095448 \times 10^{ - 2} } \hfill & {1.01725254 \times 10^{ - 1} } \hfill \\ \end{array} } \right]\)

\(\Sigma_{4} = \left[ {\begin{array}{*{20}l} {3.57531835 \times 10^{ - 2} } \hfill & {6.20042065 \times 10^{ - 2} } \hfill \\ {6.20042065 \times 10^{ - 2} } \hfill & {1.07533499 \times 10^{ - 1} } \hfill \\ \end{array} } \right]\)

\(\Sigma_{5} = \left[ {\begin{array}{*{20}l} {1.0 \times 10^{ - 6} } \hfill & {1.06496222 \times 10^{ - 29} } \hfill \\ {1.06496222 \times 10^{ - 29} } \hfill & {1.0 \times 10^{ - 6} } \hfill \\ \end{array} } \right]\)