Bayesian Inference of a Finite Population under Selection Bias

• Main Author: Xu, Zhiqing
• Other Authors: Balgobin Nandram, Advisor
• Format: Others
• Published: Digital WPI 2014
• Subjects: Bayesian; generalized gamma distribution; Gibbs sampler; size-biased sampling
• Online Access: https://digitalcommons.wpi.edu/etd-theses/621; https://digitalcommons.wpi.edu/cgi/viewcontent.cgi?article=1620&context=etd-theses

Length-biased sampling method gives the samples from a weighted distribution. With the underlying distribution of the population, one can estimate the attributes of the population by converting the weighted samples. In this thesis, generalized gamma distribution is considered as the underlying distribution of the population and the inference of the weighted distribution is made. Both the models with known and unknown finite population size are considered. In the modes with known finite population size, maximum likelihood estimation and bootstrapping methods are attempted to derive the distributions of the parameters and population mean. For the sake of comparison, both the models with and without the selection bias are built. The computer simulation results show the model with selection bias gives better prediction for the population mean. In the model with unknown finite population size, the distributions of the population size as well as the sample complements are derived. Bayesian analysis is performed using numerical methods. Both the Gibbs sampler and random sampling method are employed to generate the parameters from their joint posterior distribution. The fitness of the size-biased samples are checked by utilizing conditional predictive ordinate.