Fig. 6

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