Censored values/information

Left-censored data are characteristic of many bioassays due to the inherent limitation of the presence of a lower limit of detection and quantification. An ad hoc approach to dealing with the left-censored values is to replace them with the Unfit of quantification (LOQ) or LOQ/2 values. Alternatively, one can borrow information from other variables related to the missing values and use MI to estimate the left-censored data. In addition, the left-censored mechanism can be incorporated directly into a parametric model, and a maximum likelihood (ML) approach can be used to estimate the parameters (21). 

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