Distributions of the obtained parameters according to the evolutionary stages of the sources covering both the reliable and the candidate sample. The colours represent warm-starless, protostellar, and prestellar cores, and the black outline represents the whole sample, as indicated in the legend. The histograms are (a) NH₃ (1,1) line width, (b) NH₃ (2,2) line width, (c) NH₃ (1,1) main hyperfine component optical depth – all of which are from CLASS fitting (see Sect. 2.2) –, (d) thermal line width calculated from Eq. (6), (e) kinetic temperature calculated from Eq. (2), and (f) NH₃ column density calculated from Eq. (13).