Distributions of the estimate for the index of the power-law dependence between flux density and wavelength in the rest-frame UV (β-slope) measured from the photometry of individual galaxies for PCl J1001+0220 spec-z members and the coeval field (red and blue histograms, respectively). Measurements are made assuming a single (unbroken) power-law dependence of f_λ on λ for each galaxy following the method of Hathi et al. (2016). For galaxies at z < 4.5, β is measured with the i⁺z⁺Y J photometry spanning roughly 1300 Å < λ_rest < 2300 Å. At z > 4.5, the i⁺ band is exchanged for the H band (covering roughly 1400 Å < λ_rest < 3000 Å) to prevent Lyα emission from potentially contaminating the measurement. The average errors on individual measurements for the two samples are shown at the top left (σ_β ~ 0.2 in both cases). Galaxies where extremely blue β-slopes are measured (β < −2.5) have average errors roughly twice the global average. The median β-slope for both samples is and no significant difference is measured between the two distributions.