Reuben Cheruiyot - Academia.edu (original) (raw)

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Papers by Reuben Cheruiyot

Journal of Statistical Theory and Applications, 2020

International Journal of Statistics and Probability, Apr 27, 2019

This study explores the estimation of finite population total. For many years design-based approa... more This study explores the estimation of finite population total. For many years design-based approach dominated the scene in statistical inference in sample surveys. The scenario has since changed with emergence of the other approaches (Model-Based, Model-Assisted and the Randomization-Assisted), which have proved to rival the conventional approach. This paper focuses on a model based approach. Within this framework a nonparametric regression estimator for finite population total is developed. The nonparametric technique has been found from previous studies to be advantageous than its parametric counterpart in terms of robustness and flexibility. Kernel smoother has been used in construction of the estimator. The challenge of the boundary problem encountered with the Nadaraya-Watson estimator has been addressed by modifying it using reflection technique. The performance of the proposed estimator has been compared to the design-based Horvitz Thompson estimator and the model-based nonparametric regression estimator proposed by (Dorfman, 1992) and the ratio estimator using simulated data.

The idea of pooling samples into pools as a cost effective method of screening individuals for th... more The idea of pooling samples into pools as a cost effective method of screening individuals for the presence of a disease in a large population is discussed. Group testing was designed to reduce diagnostic cost. Testing population in pools also lower misclassification errors in low prevalence population. In this study we violate the assumption of homogeneity and perfect tests by investigating estimation problem in the presence of test errors. This is accomplished through Maximum Likelihood Estimation (MLE). The purpose of this study is to determine an analytical procedure for bias reduction in estimating population prevalence using group testing procedure in presence of tests errors. Specifically, we construct an almost unbiased estimator in pool-testing strategy in presence of test errors and compute the modified MLE of the prevalence of the population. For single stage procedures, with equal group sizes, we also propose a numerical method for bias correction which produces an almos...

In this study we have explored an estimator for finite population total under the famous predicti... more In this study we have explored an estimator for finite population total under the famous prediction approach. This approach has been compared with design-based approach using simple random sampling and stratified random sampling techniques. It is shown that the estimators under model based approach give better estimates than the estimators under design based approach both when using simple random sampling (s.r.s) and stratified random sampling. The relative absolute error from both approaches is computed and has been shown to be superior under the super population model than the design based approach. This approach is then applied to predict the total number of people living with HIV/AIDS in Nakuru Central district. Index Terms: Model-based approach, design -based approach, simple random sampling, stratified sampling, HIV/AIDS. ————————————————————