left-censored data the tobit model from the previous section assumes a normal distribution that is censored at zero. an observation of zero is considered to be left-censored. in the fit parametric survival platform, left-censored observations are specified using two response columns. in this ...
The paper also explored two-component Weibull mixture distribution (2CMWD) as a suitable model for modeling left-censored mixture data. As the explicit derivations for the estimators of the parameters are not possible, MCMC methods and Lindley's approximation (LA) have been considered for ...
ML based covariance matrix estimator for left-censored data is introduced.Computation times are decreased considerably with parallelized pairwise estimation.The proposed estimators produce unbiased estimates with reasonable variation.关键词: Maximum likelihood estimation Covariance matrix Left-censoring Non-detects...
Maximum likelihood estimation in semiparametric regression models with censored data (with Discussion) Semiparametric regression models play a central role in formulating the effects of covariates on potentially censored failure times and in the joint modell... D Zeng,DY Lin - 《Journal of the Royal ...
However, enteric virus density in water often falls below the quantification limit (non-detect) of the analytical methods employed, and it is always difficult to apply stochastic models to a dataset with a substantially high number of non-detects, i.e., left-censored data. We applied a ...
Using the proposed method, estimates obtained with data artificially censored at 500 copies/ml were close to those obtained with the real data set. 展开 关键词: Left-censoring Linear mixed effects model Repeated measures DOI: 10.1093/biostatistics/1.4.355 被引量: 193 ...
The main classes of statistical treatment of below-detection limit (left-censored) environmental data for the determination of basic statistics that have been used in the literature are substitution methods, maximum likelihood, regression on order statistics (ROS), and nonparametric techniques. These tre...
We used methods for left-censored data, as substitution of non-detects can create bias. Perfluorooctane sulfonate (PFOS) was found in all soft tissues and in tail feathers. Perfluorooctanoate (PFOA) levels were high in tail feathers, but not in soft tissues. External contamination with PFOA ...
The main classes of statistical treatments that have been used to determine if two groups of censored environmental data arise from the same distribution are substitution methods, maximum likelihood (MLE) techniques, and nonparametric methods. These treatments along with using all instrument-generated dat...
We propose a multivariate parametric cure model that can be used with left-censored and right-censored data. Our model allows for the estimation of the time to screening as well as the average number of times individuals will be screened. We calculate likelihood functions based on the ...