x₁, c, and Hubble residual correlations with host galaxy parameters – stellar mass, oxygen abundance, sSFR, and HαEW – for the aperture-corrected sample (in blue) and the g-band fraction sample (in red). Solid transparent lines are the 10 000 individual slopes found with the LINMIX MCMC sampler, with the average slope as a solid line on top. Overplotted there are the average and standard deviation of the variable on the Y-axis in each of the two high and low bins in the X-axis variable, which has been divided using the median X value as the split point. The height of the box represents the error of the mean in each bin.