Retrieved normalized posterior distributions of model parameters for the 20 noise realizations. The posteriors of the individual noise realizations are plotted in light gray. The more posteriors overlap, the darker the gray becomes. The green dash-dotted line marks the mean, the blue dashed line the median of the posteriors for the different noise realizations. The posteriors found in the retrieval on the nonrandomized spectrum are plotted in solid red. The dotted line marks the true value for the Earth-twin atmosphere. Absence of the dotted line indicates that the species were not present in the atmosphere used to generate the input spectrum.