Volume averaged G_eff compared to the G_eff expected from the background ρ_m. The scale factor a is along the horizontal axis. Here, θ = −1.7. At early times when voids have not yet developed, effects of voids are negligible and therefore the averaged G_eff and G_eff for the average density agree with each other. On the other hand, at late times when voids are present, they deviate from each other due to the lower density in voids.