Mixed-Effects Tobit Joint Models for Longitudinal Data with Skewness, Detection Limits, and Measurement Errors

Figure 2

The goodness-of-fit. (a–c): Residuals versus fitted values of ln(RNA) under skew-normal (SN), skew-t (ST), and normal (𝑁) models based on the JM method; the values below detection limit (ln(50)) are not included in the plots since there are no corresponding residuals but only predicted values. (d–f): Observed values versus fitted values of ln(RNA) under SN, ST, and N models, where the horizontal line at ln(50) represents the detection limit.

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