Sample size of exoEarths required to detect an injected trend in albedo. Top panels represent the true-positive rate or statistical power as a function of the sample size of exoEarths, N_EEC, for two threshold values of the Bayes factor, K. Bottom subplots show the false-positive rate as a function of sample size. For each point in these subplots an analysis similar to that in Figure 3 was performed using 10,000 simulations of planetary samples at that sample size. Simulations injected a strong albedo trend with ΔA = 0.4.