Results of re-running our analysis on a modified version of the first quadrant data, in which random noise was added. In each panel, the dashed blue line indicates the value derived from the first quadrant data without noise added; in panels (c) through (f), a pair of dotted lines above and below the blue dashed line indicates the estimated error bars on that value, as presented in Section 4. (a) The number of clouds identified in the first quadrant. (b) The total mass of those clouds. (c) The multiplicative coefficient A of the size-linewidth relation. (d) The power-law slope β of the size-linewidth relation. (e) The truncation mass M₀ of the truncated power-law cloud mass spectrum. (f) The power index γ of the mass spectrum. In panels (c) through (f), only inner galaxy parameters are shown, for simplicity.