Statistical methods in ophthalmology: an adjusted chi-square approach.

abstract：:This article is motivated by a lung cancer study where a regression model is involved and the response variable is too expensive to measure but the predictor variable can be measured easily with relatively negligible cost. This situation occurs quite often in medical studies, quantitative genetics, and ecological and ...

journal_title：Biometrics

authors： Chen Z,Wang YG

更新日期：2004-12-01 00:00:00

abstract：:Truncation is a well-known phenomenon that may be present in observational studies of time-to-event data. While many methods exist to adjust for either left or right truncation, there are very few methods that adjust for simultaneous left and right truncation, also known as double truncation. We propose a Cox regressi...

journal_title：Biometrics

authors： Rennert L,Xie SX

更新日期：2018-06-01 00:00:00

abstract：:Five procedures are considered for the comparison of two or more multivariate samples. These procedures include a newly proposed nonparametric rank-sum test and a generalized least squares test. Also considered are the following tests: ordinary least squares, Hotelling's T2, and a Bonferroni per-experiment error-rate ...

journal_title：Biometrics

authors： O'Brien PC

更新日期：1984-12-01 00:00:00

abstract：:In this article, we present an estimation approach for solving nonlinear constrained generalized estimating equations that can be implemented using object-oriented software for nonlinear programming, such as nlminb in Splus or fmincon and lsqnonlin in Matlab. We show how standard estimating equation theory includes th...

journal_title：Biometrics

authors： Contreras M,Ryan LM

更新日期：2000-12-01 00:00:00

abstract：:The data set presented relates a binomial response to ordered levels of an explanatory variable, representing doses of a drug, with data collected at several centers. A study goal is to test independence of the response and the ordinal factor, assuming under the alternative only that the binomial parameter is a monoto...

journal_title：Biometrics

authors： Agresti A,Coull BA

更新日期：1996-09-01 00:00:00

abstract：:In this article, we demonstrate a statistical method for fitting the parameters of a sophisticated network and epidemic model to disease data. The pattern of contacts between hosts is described by a class of dyadic independence exponential-family random graph models (ERGMs), whereas the transmission process that runs ...

journal_title：Biometrics

authors： Groendyke C,Welch D,Hunter DR

更新日期：2012-09-01 00:00:00

abstract：:The search for an optimal dose of a drug has been investigated in a sequential setting to ensure the safety level by Eichhorn and Zacks (1973, Journal of the American Statistical Association 68, 594-598; 1981, Communications in Statistics--Theory and Methods A10, 931-953), Eichhorn (1974, Communications in Statistics ...

journal_title：Biometrics

authors： Shih WJ

更新日期：1989-06-01 00:00:00

abstract：:A ranked set sampling procedure with unequal samples (RSSU) is proposed and used to estimate the population mean. This estimator is then compared with the estimators based on the ranked set sampling (RSS) and median ranked set sampling (MRSS) procedures. It is shown that the relative precisions of the estimator based ...

journal_title：Biometrics

authors： Bhoj DS

更新日期：2001-09-01 00:00:00

abstract：:One common method for estimating total catch is to multiply an estimate for CPUE, the catch per unit effort, by an estimate of total effort obtained from an independent second survey. In general, estimating total effort requires that sample times are chosen at random over the full fishing period; however, in practice,...

journal_title：Biometrics

authors： Dauk PC,Schwarz CJ

更新日期：2001-06-01 00:00:00

abstract：:When comparing follow-up measurements from two independent populations, missing records may arise due to censoring by events whose occurrence is associated with baseline covariates. In these situations, inferences based only on the completely followed observations may be biased if the follow-up measurements and the co...

journal_title：Biometrics

authors： Cheung YK

更新日期：2005-06-01 00:00:00

abstract：:Tag loss in mark-recapture experiments is a violation of one of the Jolly-Seber model assumptions. It causes bias in parameter estimates and has only been dealt with in an ad hoc manner. We develop methodology to estimate tag retention and abundance in double-tagging mark-recapture experiments. We apply this methodolo...

journal_title：Biometrics

authors： Cowen L,Schwarz CJ

更新日期：2006-09-01 00:00:00

abstract：:The validation of surrogate endpoints has been studied by Prentice (1989, Statistics in Medicine 8, 431-440) and Freedman, Graubard, and Schatzkin (1992, Statistics in Medicine 11, 167-178). We extended their proposals in the cases where the surrogate and the final endpoints are both binary or normally distributed. Le...

journal_title：Biometrics

authors： Buyse M,Molenberghs G

更新日期：1998-09-01 00:00:00

abstract：:A class of adaptive weighted log-rank statistics is described where the vector of weights is chosen in a data-dependent way from a family of "smooth" weight vectors. A parametric family of weight vectors is identified which includes most shapes of weighting vectors that will be near optimal in many cancer prevention a...

journal_title：Biometrics

authors： Self SG

更新日期：1991-09-01 00:00:00

abstract：:The feasibility and cost-effectiveness of estimation of kappa using a case-control method of sampling, proposed by Jannarone, Macera, and Garrison (1987, Biometrics 43, 433-437), is provided support. However, in this article unrealistic assumptions in their presentation are identified and more general results for more...

journal_title：Biometrics

authors： Kraemer HC,Bloch DA

更新日期：1990-03-01 00:00:00

abstract：:Left truncation commonly occurs in many areas, and many methods have been proposed in the literature for the analysis of various types of left-truncated failure time data. For the situation, a common approach is to conduct the analysis conditional on truncation times, and the method is relatively simple but may not be...

journal_title：Biometrics

authors： Wang P,Li D,Sun J

更新日期：2020-10-15 00:00:00

abstract：:It has become increasingly common in epidemiological studies to pool specimens across subjects to achieve accurate quantitation of biomarkers and certain environmental chemicals. In this article, we consider the problem of fitting a binary regression model when an important exposure is subject to pooling. We take a re...

journal_title：Biometrics

authors： Zhang Z,Albert PS

更新日期：2011-06-01 00:00:00

abstract：:We propose a similarity-based regression method to detect associations between traits and multimarker genotypes. The model regresses similarity in traits for pairs of "unrelated" individuals on their haplotype similarities, and detects the significance by a score test for which the limiting distribution is derived. Th...

journal_title：Biometrics

authors： Tzeng JY,Zhang D,Chang SM,Thomas DC,Davidian M

更新日期：2009-09-01 00:00:00

abstract：:In matched case-control studies one frequently must consider more than one variable in the analysis and in this paper a log-linear model is presented to meet this objective. A conditional argument yields a method for making inferences on the parameters measuring the association between the variables and disease. The r...

journal_title：Biometrics

authors： Holford TR

更新日期：1978-12-01 00:00:00

abstract：:The standard approach to inference for random effects meta-analysis relies on approximating the null distribution of a test statistic by a standard normal distribution. This approximation is asymptotic on k, the number of studies, and can be substantially in error in medical meta-analyses, which often have only a few ...

journal_title：Biometrics

authors： Follmann DA,Proschan MA

更新日期：1999-09-01 00:00:00

abstract：:For many long-lived animal species, individuals do not breed every year, and are often not accessible during non-breeding periods. Individuals exhibit site fidelity if they return to the same breeding colony or spawning ground when they breed. If capture and recapture is only possible at the breeding site, temporary e...

journal_title：Biometrics

authors： Pledger S,Baker E,Scribner K

更新日期：2013-12-01 00:00:00

abstract：:In studies of serial cancer markers or disease states and their relation to survival, data on the marker or state are usually obtained at infrequent time points during follow-up. A Markov model is developed to assess the dependence of risk of death on marker level or disease state and inferences within this model are ...

journal_title：Biometrics

authors： Kay R

更新日期：1986-12-01 00:00:00

abstract：:A common measure in clinical trials and epidemiologic studies is the number of events such as seizures, hospitalizations, or bouts of disease. Frequently, a binary measure of severity for each event is available but is not incorporated in the analysis. This paper proposes methodology for jointly modeling the number of...

journal_title：Biometrics

authors： Albert PS,Follmann DA,Barnhart HX

更新日期：1997-09-01 00:00:00

abstract：:Capture-recapture models were originally developed to account for encounter probabilities that are less than 1 in free-ranging animal populations. Nowadays, these models can deal with the movement of animals between different locations and are also used to study transitions between different states. However, their use...

journal_title：Biometrics

authors： Pradel R

更新日期：2005-06-01 00:00:00

abstract：:Image-on-image regression analysis, using images to predict images, is a challenging task, due to (1) the high dimensionality and (2) the complex spatial dependence structures in image predictors and image outcomes. In this work, we propose a novel image-on-image regression model, by extending a spatial Bayesian laten...

journal_title：Biometrics

authors： Guo C,Kang J,Johnson TD

更新日期：2020-12-27 00:00:00

abstract：:Gene-disease association studies based on case-control designs may often be used to identify candidate polymorphisms (markers) conferring disease risk. If a large number of markers are studied, genotyping all markers on all samples is inefficient in resource utilization. Here, we propose an alternative two-stage metho...

journal_title：Biometrics

authors： Satagopan JM,Venkatraman ES,Begg CB

更新日期：2004-09-01 00:00:00

abstract：:We develop a parameterization of the beta-binomial mixture that provides sensible inferences about the size of a closed population when probabilities of capture or detection vary among individuals. Three classes of mixture models (beta-binomial, logistic-normal, and latent-class) are fitted to recaptures of snowshoe h...

journal_title：Biometrics

authors： Dorazio RM,Royle JA

更新日期：2003-06-01 00:00:00

abstract：:This article proposes a two-stage simultaneous confidence procedure for the comparisons of k pairs of population means, without using multiplicity adjustment of more than two populations. The proposed procedure can be broadly applied to parametric or nonparametric models. It is robust and versatile because its derivat...

journal_title：Biometrics

authors： Chen JT

更新日期：2008-06-01 00:00:00

abstract：:A method is developed for obtaining tree-structured relative risk estimates for censored survival data. The first step of a full likelihood estimation procedure is used in a recursive partitioning algorithm that adopts most aspects of the widely used Classification and Regression Tree (CART) algorithm of Breiman et al...

journal_title：Biometrics

authors： LeBlanc M,Crowley J

更新日期：1992-06-01 00:00:00

abstract：:We propose a nonparametric Bayesian approach to estimate the natural direct and indirect effects through a mediator in the setting of a continuous mediator and a binary response. Several conditional independence assumptions are introduced (with corresponding sensitivity parameters) to make these effects identifiable f...

journal_title：Biometrics

authors： Daniels MJ,Roy JA,Kim C,Hogan JW,Perri MG

更新日期：2012-12-01 00:00:00

abstract：:Stepped wedge designed trials are a type of cluster-randomized study in which the intervention is introduced to each cluster in a random order over time. This design is often used to assess the effect of a new intervention as it is rolled out across a series of clinics or communities. Based on a permutation argument, ...

journal_title：Biometrics

authors： Hughes JP,Heagerty PJ,Xia F,Ren Y

更新日期：2020-03-01 00:00:00