Table 2.

Reference mean estimation.

Reference Mean	Equation
Euclidean	$C_e=\frac{1}{N}\sum _i{C}_i$
Harmonic	$C_h={\left(\frac{1}{N}\sum _i{C}_i^{-1}\right)}^{-1}$
Log Euclidean	$C_{le}={\text{exp}}_m\left(\frac{1}{N}\sum _i{\text{log}}_m{C}_i\right)$
Riemannian Mean	$C_r=\text{argmin}\left(\sum _i{\delta }_R{\left(C_e{C}_i\right)}^2\right)$
Kullback	$C_k=C_e^{1/2}{\left(C_e^{-1/2}{C}_h{C}_e^{-1/2}\right)}^{\alpha }{C}_e^{1/2}$

$C_i$ denotes the functional connectivity matrix for subject i.