1D and 2D marginal posterior distributions of the set of population parameters, ϕ, for each of the four models described in Sect. 4.3. The dashed lines indicate the mode of the posterior samples, and values are reported as the mode with the 68 per cent HDP interval. Panel (a): 1D marginal posterior of the population parameter ϕ_const = μ (blue), describing the constant escape fraction value most likely to describe all galaxies in the sample. Panel (b): Corner plot showing the 1D and 2D marginal posterior distributions of the set of population parameters ϕ_lognorm (pink), describing a log-normal distribution of escape fractions. Here μ and σ represent, respectively, the mean and standard deviation of the natural logarithm of the escape fraction. Panel (c): 1D marginal posterior of the population parameter ϕ_exp = μ (orange), which represents the scale parameter in an exponential distribution of escape fractions. Panel (d): Corner plot containing the 1D and 2D marginal posteriors for the set of population parameters ϕ_bimodal (green), which describes a bimodal distribution of escape fractions: w denotes the fraction of galaxies with a constant escape fraction equal to zero, while μ and σ describe the escape fraction of the remaining galaxies as being normally distributed.