Structure functions S₂(ℓ) calculated from the Gaussian polarization models corresponding to f_M = 1.0 and α_M = −2.5 (circles) and α_M = −1.5 (squares), with angular resolutions δ = 2′ (orange and red), 10′ (blue and magenta). The dashed lines with open symbols, shown in orange and blue, correspond to S₂(ℓ) calculated using only the values of Q_M and U_M towards lines of sights with starlight polarization observations towards each region. The solid lines with filled symbols, shown in red and magenta, correspond to S₂(ℓ) calculated using 10 000 LOSs randomly distributed overin each region. In the lower plot of each panel, we present the differences, (dark green), and (light green). There is no noise included in the Gaussian models of polarization, so no bias correction is necessary.