Table 4.

Summary of key observations from Figures 2, 3.

Absolute power	Relative power
Eyes-closed Boys >Girls: wide spread sex differences in both hemispheres and across low and high frequencies The differences were more pronounced in the posterior sites, with the right-hemisphere having larger differences between the sexes. Specifically, O2, PO8, and P4 had the largest inter-sex differences at δ, θ, α1–α2, and higher bands β1–γ1 frequency bands. Frontal sites (F3, and F8) also showed boys with a larger spectral power for the frequency bands spanning from θ to β4. Age factor: A significant age relationship was observed across the two hemispheres, at both anterior and posterior sites, and at lower frequencies δ, θ, and α1. Negative correlation between spectral power and age was observed prominently at very low (δ, θ) and very high (β4–γ4)	Eyes-closed Boys >Girls: both hemispheres (anterior and posterior regions), mainly in θ, α1, α2 bands Age factor was strongly present at the anterior and posterior sites of both hemispheres at both very low (δ) and high frequency bands (α2 and above), particularly in the occipital sites. There was a negative correlation with age at δ, and a positive correlation with age at α2 and higher bands for both sexes. This suggests that relative spectral powers are increased at higher frequencies with age and become lower at the very low δ
Eyes-open Virtually identical to eyes-closed condition in terms of Boys >Girls, and similar observations for the location and frequency of the sex and age factors	Eyes-open Similar pattern to eyes-closed for the sex factor, in terms of boys >girls at θ, α1, α2 bands Relative spectral powers of both boys and age show age dependence concentrated in the occipital sites. Similar to eyes-closed, positive age correlation for β1–β3 bands