Table 4: Median and dispersion of the log-normal distribution for the fractional polarization, , as a function of frequency and for the different radio source populations relevant at CMB frequencies. Two cases are considered, a more “optimistic” one and a more “conservative” one (see Section 5.1).

GHz GHz Steep FSRQ BL Lac Steep FSRQ BL Lac Lower case (more “optimistic”) (%) 3.0 2.0 2.5 4.0 2.5 3.0 (%) 5.0 3.0 3.5 6.0 3.5 4.2 Upper case (more “conservative”) (%) 4.0 3.0 3.6 5.0 3.6 4.3 (%) 6.0 3.8 4.5 7.0 4.6 5.5