Logarithm of residuals Regression model $\ln {\sigma }_i^2$ on principal components $z_i$

R²

Pr (>|t|)

$\ln e_i^2=-336.0304-976.4507\ln z_1+1.2851\ln z_2+978.9833\ln z_3$

0.1547

0.1102

0.0484

0.1109