Sham Dean

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thanga raja

M.S.University, Tirunelveli

Jenny Li

Ohio State University

Rahim Tahmasebi

Bushehr Medical School

Mersin University

University of East London

Gwen Robbins Schug

University of North Carolina at Greensboro

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Papers by Sham Dean

Bayesian sample-size determination for one and two Poisson rate parameters with applications to quality control

Journal of Applied Statistics, 2006

Page 1. Bayesian Sample-size Determination for One and Two Poisson Rate Parameters with Applicati... more

Bayesian sample size determination for normal means and differences between normal means

Journal of the Royal Statistical Society: …, 1997

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Bayesian and mixed Bayesian/likelihood criteria for sample size determination

Statistics in Medicine, 1997

Sample size estimation is a major component of the design of virtually every experiment in medici... more Sample size estimation is a major component of the design of virtually every experiment in medicine. Prudent use of the available prior information is a crucial element of experimental planning. Most sample size formulae in current use employ this information only in the form of point estimates, even though it is usually more accurately expressed as a distribution over a range of values. In this paper, we review several Bayesian and mixed Bayesian/likelihood approaches to sample size calculations based on lengths and coverages of posterior credible intervals. We apply these approaches to the design of an experiment to estimate the difference between two binomial proportions, and we compare results to those derived from standard formulae. Consideration of several criteria can contribute to selection of a final sample size.

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Bayesian Sample Size Determination for Case-Control Studies

Journal of The American Statistical Association, 2006

Case-control studies are among the most commonly used means of assessing association between expo... more Case-control studies are among the most commonly used means of assessing association between exposure and outcome. Sample size determination and the optimal control-to-case ratio are vital to the design of such studies. In this article we investigate Bayesian sample size determination and the control-to-case ratio for case-control studies, when interval estimation is the goal of the eventual statistical analysis. In certain cases we are able to derive approximate closed-form sample size formulas. We also describe two Monte Carlo methods, each of which provides a unified approach to the sample size problem, because they may be applied to a wide range of interval-based criteria. We compare the accuracy of the different methods. We also extend our methods to include cross-sectional designs and designs for gene-environment interaction studies.

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Sample size determination in Bayesian analysis

The Statistician, 1992

... New York, Springer). De Groot, M. (1985) Probability and Statistics, 2nd edn (Reading, MA, Ad... more

Bayesian techniques for sample size determination in clinical trials: a short review

Statistical methods in medical research, 2003

The aim of this paper is to review some key techniques of Bayesian methods of sample size determi... more The aim of this paper is to review some key techniques of Bayesian methods of sample size determination. The approach is to cover a small number of simple problems, such as estimating the mean of a normal distribution. The methods considered are in two groups: inferential and decision theoretic. In the inferential Bayesian methods of sample size determination, we are solely concerned with the inference about the parameter(s) of interest. The fully Bayesian or decision theoretic approach treats the problem as a decision problem and employs a loss or utility function.

Bayesian Sample Size Determination Using Linex Loss and Linear Cost

Communications in Statistics-theory and Methods, 2012

Sample size determination (SSD) is an important issue to consider when estimating any parameter. ... more Sample size determination (SSD) is an important issue to consider when estimating any parameter. A number of researchers have studied the Bayesian SSD problem. One group considered utility (or loss) functions and cost functions in their SSD problem and the others did not. Among the former, most of the SSD problems are based on symmetric squared error (SE) loss function. On the other hand, in a situation when under estimation is more serious than overestimation or vice versa, then an asymmetric loss function should be used. In such a situation how many samples do we need to take to estimate the parameter under study? In this article, we consider sample size using the asymmetric linex loss function and a linear cost function for various distributions. We compare the sample size obtained from this asymmetric loss function with the sample size from the symmetric SE loss function. We also consider the situation where it is not worth sampling due to high sampling cost or strong prior information.

Sample size calculations for binomial proportions via highest posterior density intervals

The Statistician, 1995

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Sample size determination: a review

Journal of The Royal Statistical Society Series D-the Statistician, 1997

This paper is concerned with methods of sample size determination. The approach is to cover a sma... more This paper is concerned with methods of sample size determination. The approach is to cover a small number of simple problems, such as estimating the mean of a normal distribution or the slope in a regression equation, and to present some key techniques. The methods covered are in two groups: frequentist and Bayesian. Frequentist methods specify a null and alternative hypothesis for the parameter of interest and then find the sample size by controlling both size and power. These methods often need to use prior information but cannot allow for the uncertainty that is associated with it. By contrast, the Bayesian approach offers a wide variety of techniques, all of which offer the ability to deal with uncertainty associated with prior information.

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Bayesian sample-size determination for one and two Poisson rate parameters with applications to quality control

Journal of Applied Statistics, 2006

Page 1. Bayesian Sample-size Determination for One and Two Poisson Rate Parameters with Applicati... more