Figure 3: (a) Correlation between fractional polarizations at 4.8 and 20 GHz for flat-spectrum sources with mJy. Green points indicate upper limits in at 20 GHz, red points at 4.8 GHz, and blue points at the both frequencies. The solid line is the linear regressions found by the ASURV code (see the text). (b) The fractional polarization at 20 GHz as a function of the flux density at the same frequency (green points indicate upper limits in ).