Journal of Probability and Statistics / 2012 / Article / Fig 1

Research Article

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

Figure 1

The histograms (a,b) of viral load measured from RNA levels (in natural l n scale) and standardized CD4 cell count in plasma for 44 patients in an AIDS clinical trial study. Profiles (c,d) of viral load (response) in l n scale and CD4 cell count (covariate) for three randomly selected patients. The vertical and horizontal lines in (a) and (c) are below the detectable level of viral load ( 3 . 9 1 = l n ( 5 0 ) ).
(a) Histogram of viral load in ln scale
(b) Profiles of viral load in ln scale
(c) Profiles of CD4 cell count
(d) Histogram of CD4 cell count

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