Linear Regression
The connectivity spread measure was modelled to linearly vary with age
and change in power. This was done separately for each frequency band
and seed electrode group. Robust linear regression was used to minimize
the effect of outliers (“Regression,” 2009), using the ‘fitlm’
function in MATLAB.
\begin{equation}
\text{Conn}\left(f\right)=b_{c}+b_{\text{age}}*age+b_{\text{power}}*power\left(f\right)\nonumber \\
\end{equation}The p-value for each of the coefficients was computed for the
t-statistic of the two-sided hypothesis test \((H:b=0)\), given the
other terms in the regression model.