Total temperature dispersion within R₅₀₀ as a function of the overall cluster temperature. Left: Relation between the mean cluster temperature T₅₀₀ and the intrinsic scatter σ_Tint within R₅₀₀. The dotted orange line represents the best-fit relation to the measured points and is compared to the observations by Frank et al. (2013; black) and simulations with (green) and without (cyan) thermal conduction by Rasia et al. (2014). Right: Relative scatter as function of the cluster temperature. In blue, we show the observed values (i.e., total scatter σ_Ttot/T₅₀₀), in green we plot the relative intrinsic scatter (i.e., σ_Tint/T₅₀₀) computed as given in Eq. (13) where the statistical errors (i.e., ϵ_{T1D, j, stat}) are shown in pink and are computed using Eq. (4), in magenta we show the scatter associated with the underlying temperature profile (i.e., σ_Tprof/T₅₀₀), and in red the average statistical uncertainty of the T_2D, i measurements (i.e., ϵ_{T2D, i, stat}).