Fig. 4

Distributions for simulated total depressive symptom scores with a log-normal scale when the latent trait was set to an exponential distribution with a parameter of λ = 1. Exponential distribution with a parameter of λ = 1 were used for the latent trait of depressive symptoms, and normal distributions with standard deviations of 1 (a), 2 (b), 3 (c), and 4 (d) were applied for the threshold of depressive symptom items