Cumulative distributions of the linewidths (left panel), mean excitation temperatures (middle panel), and the logarithm of the virial parameters (right panel) for spiral-arm and inter-arm clumps are shown as the solid blue and orange lines, respectively. The samples are distance-limited with 6 kpc ≤ d_k < 9 kpc, and excludeclumps with masses below the nominal completeness limit at 9 kpc. The distributions for the Sagittarius and Scutum arms, which contribute to the spiral-arm distribution, are also shown as the thin purple and cyan lines, respectively.The dashed vertical lines show the means of the spiral-arm and inter-arm distributions.