Comparison between the full spectrum fitting residuals and propagated errors in the CAVITY datacubes using a Voronoi spatial binning scheme. Top-left panel: Residual spectrum averaged over all Voronoid bins and all the CAVITY galaxies analysed. Middle-left panel: Mean of the ratio between the residuals and the propagated errors ((O − M)/ϵ) as a function of wavelength. Bottom-left panel: Dispersion of (O − M)/ϵ as a function of wavelength. Right panel: Global distribution of the (O − M)/ϵ. Red horizontal lines of gradual thickness are plotted in each panel for the mean value, mean ±σ, and mean ±3σ. A Gaussian distribution representative of the mean and dispersion of the (O − M)/ϵ distribution is represented in the right-hand panel. In this analysis regions flagged as bad by the reduction pipeline have been masked from each individual spectrum as well as the 5577 Å sky line.