Mean duration as a function of frequency for all the type III bursts, as found from the FWHM. The blue dashed lines show the spread in the data from the standard deviation. The red dashed line shows the fit t_D = (3.7 ± 0.2) f^{−0.86±0.11} for the frequency (per 30 MHz). The purple diamonds show the FWHM found from Aubier & Boischot (1972) and Barrow & Achong (1975). The purple pluses and triangles show the FWHM for fundamental and harmonic bursts, respectively, from Tsybko (1989). The purple squares show the FWHM for powerful (> 1000 SFU) type III bursts, from Mel’Nik et al. (2011). The orange and green dashed lines show the fit in frequency (per 30 MHz) of t_D = 7.3f⁻¹ reported by Suzuki & Dulk (1985) and t_D = 6.2f^−2∕3 reported by Elgaroy & Lyngstad (1972), respectively.