Notes. Diagonal blocks give the rms values for half-ring sums (“Freq.”) and differences (“Diff.”) of single-frequency maps. Off-diagonal blocks give the same quantities for frequency-difference maps (70 GHz−100 GHz, 70 GHz−143 GHz, and 100 GHz−143 GHz). As described in the text, the maps are smoothed to a common resolution of 15′, somewhat lower than the resolution of the 70 GHz maps. In addition, structure on scales larger than 8° is determined and removed from all maps to avoid introducing biases from residual monopoles and dipoles, so that only structure from 15′ to 8° in angular scale is included in these calculations.