Combining multivariate bioassays.

abstract：:A method is presented for choosing an additive constant c when transforming data x to y = log(x + c). The method preserves Type I error probability and power in ANOVA under the assumption that the x + c for some c are log-normally distributed. The method has advantages similar to those of rank transformations--namely,...

journal_title：Biometrics

authors： Berry DA

更新日期：1987-06-01 00:00:00

abstract：:Multistage selection with fixed proportions and selection indices based on covariates of the target variable is studied. Assuming a multivariate normal distribution before the selection, expressions are presented for the expectation and the variance of the target variable in the retained subpopulation. As the numerica...

journal_title：Biometrics

authors： Norell L,Arnason T,Hugason K

更新日期：1991-03-01 00:00:00

abstract：:Inference regarding the inclusion or exclusion of random effects in linear mixed models is challenging because the variance components are located on the boundary of their parameter space under the usual null hypothesis. As a result, the asymptotic null distribution of the Wald, score, and likelihood ratio tests will ...

journal_title：Biometrics

authors： Lee OE,Braun TM

更新日期：2012-06-01 00:00:00

abstract：:Dose-response models are intensively used in herbicide bioassays. Despite recent advancements in the development of new herbicides, statistical analyses are commonly based on asymptotic approximations that are sometimes poor. This paper presents the use of recent results in higher order asymptotics for likelihood-base...

journal_title：Biometrics

authors： Bellio R,Jensen JE,Seiden P

更新日期：2000-12-01 00:00:00

abstract：:In multivariate recurrent event data regression, observation of recurrent events is usually terminated by other events that are associated with the recurrent event processes, resulting in informative censoring. Additionally, some covariates could be measured with errors. In some applications, an instrumental variable ...

journal_title：Biometrics

authors： Yu H,Cheng YJ,Wang CY

更新日期：2018-09-01 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

abstract：:Brownie, Boos, and Hughes-Oliver (1990, Biometrics 46, 259-266) suggested a modification to the fixed-effects analysis of variance (ANOVA) F test for use in situations where treatments are likely to affect mean response while simultaneously increasing between-subject variability. These authors suggest that the modifie...

journal_title：Biometrics

authors： Blair RC,Sawilowsky S

更新日期：1993-09-01 00:00:00

abstract：:The distribution of health care payments to insurance plans has substantial consequences for social policy. Risk adjustment formulas predict spending in health insurance markets in order to provide fair benefits and health care coverage for all enrollees, regardless of their health status. Unfortunately, current risk ...

journal_title：Biometrics

authors： Zink A,Rose S

更新日期：2020-09-01 00:00:00

abstract：:In this paper, a Markov process is developed as a mathematical model to study the general problem of quality control monitoring. This approach was previously used by Arnold (1970) in development of sampling plans to study the water quality monitoring of streams. Arnold considered the expected sample size required for ...

journal_title：Biometrics

authors： Smeach SC,Jernigan RW

更新日期：1977-03-01 00:00:00

abstract：:Conventional statistical determinations of sample size in phase II studies typically lead to sample sizes of the order of 25 (Schoenfeld, 1980, International Journal of Radiation Oncology, Biology and Physics 6, 371-374). When the development of new treatments is proceeding rapidly relative to the recruitment of suita...

journal_title：Biometrics

authors： Whitehead J

更新日期：1985-06-01 00:00:00

abstract：:We present a natural generalization of the Buckley-James-type estimator for traditional survival data to right-censored length-biased data under the accelerated failure time (AFT) model. Length-biased data are often encountered in prevalent cohort studies and cancer screening trials. Informative right censoring induce...

journal_title：Biometrics

authors： Ning J,Qin J,Shen Y

更新日期：2011-12-01 00:00:00

abstract：:Functional mapping is a useful tool for mapping quantitative trait loci (QTL) that control dynamic traits. It incorporates mathematical aspects of biological processes into the mixture model-based likelihood setting for QTL mapping, thus increasing the power of QTL detection and the precision of parameter estimation. ...

journal_title：Biometrics

authors： Yang J,Wu R,Casella G

更新日期：2009-03-01 00:00:00

abstract：:The basic problem under consideration is the comparison of treatments with respect to a response Y when a covariable X is taken into account. Various methods involving matching may be regarded as compromises between the standard analysis of covariance and the standard analysis of independent matched pairs. First, ther...

journal_title：Biometrics

authors： Quade D

更新日期：1982-09-01 00:00:00

abstract：:Identifying disease-associated changes in DNA methylation can help us gain a better understanding of disease etiology. Bisulfite sequencing allows the generation of high-throughput methylation profiles at single-base resolution of DNA. However, optimally modeling and analyzing these sparse and discrete sequencing data...

journal_title：Biometrics

authors： Zhao K,Oualkacha K,Lakhal-Chaieb L,Labbe A,Klein K,Ciampi A,Hudson M,Colmegna I,Pastinen T,Zhang T,Daley D,Greenwood CMT

更新日期：2020-05-21 00:00:00

abstract：:This paper proposes a two-stage phase I-II clinical trial design to optimize dose-schedule regimes of an experimental agent within ordered disease subgroups in terms of the toxicity-efficacy trade-off. The design is motivated by settings where prior biological information indicates it is certain that efficacy will imp...

journal_title：Biometrics

authors： Lin R,Thall PF,Yuan Y

更新日期：2020-03-01 00:00:00

abstract：:Three properties of interest in bioavailability studies using compartmental models are the area under the concentration curve, the maximum concentration, and the time to maximum concentration. Methods are described for finding designs that minimize the variance of the estimates of these quantities in such a model. The...

journal_title：Biometrics

authors： Atkinson AC,Chaloner K,Herzberg AM,Juritz J

更新日期：1993-06-01 00:00:00

abstract：:We propose a sequential approach for constructing multiple-objective locally optimal designs for nonlinear models. The technique used here is a general one and we demonstrate the added benefits of using a multiple-objective design over a single-objective design with examples from biomedical studies. ...

journal_title：Biometrics

authors： Huang YC,Wong WK

更新日期：1998-12-01 00:00:00

abstract：:Objective measures of oxygen consumption and carbon dioxide production by mammals are used to predict their energy expenditure. Since energy expenditure is not directly observable, it can be viewed as a latent construct with multiple physical indirect measures such as respiratory quotient, volumetric oxygen consumptio...

journal_title：Biometrics

authors： Tekwe CD,Zoh RS,Bazer FW,Wu G,Carroll RJ

更新日期：2018-03-01 00:00:00

abstract：:An adjusted rank correlation test is proposed as a technique for identifying publication bias in a meta-analysis, and its operating characteristics are evaluated via simulations. The test statistic is a direct statistical analogue of the popular "funnel-graph." The number of component studies in the meta-analysis, the...

journal_title：Biometrics

authors： Begg CB,Mazumdar M

更新日期：1994-12-01 00:00:00

abstract：:This paper considers the impact of bias in the estimation of the association parameters for longitudinal binary responses when there are drop-outs. A number of different estimating equation approaches are considered for the case where drop-out cannot be assumed to be a completely random process. In particular, standar...

journal_title：Biometrics

authors： Fitzmaurice GM,Lipsitz SR,Molenberghs G,Ibrahim JG

更新日期：2001-03-01 00:00:00

abstract：:We describe a Bayesian quantile regression model that uses a confirmatory factor structure for part of the design matrix. This model is appropriate when the covariates are indicators of scientifically determined latent factors, and it is these latent factors that analysts seek to include as predictors in the quantile ...

journal_title：Biometrics

authors： Burgette LF,Reiter JP

更新日期：2012-03-01 00:00:00

abstract：:We assess the efficiency of balanced treatment allocation methods in clinical trials for comparing treatments with respect to survival. We compare optimal designs for each of three standard survival analysis techniques (maximum partial likelihood estimation, log-rank test, exponential regression) with balanced designs...

journal_title：Biometrics

authors： Kalish LA,Harrington DP

更新日期：1988-09-01 00:00:00

abstract：:The basic technical facts of human cytogenetics and the laboratory methods employed in chromosome research are explained in simple terms. The main variables used to describe chromosome images are defined and discussed. Three discriminant analysis models for chromosome classification are developed: one in which each ch...

journal_title：Biometrics

authors： Habbema JD

更新日期：1979-03-01 00:00:00

abstract：:Estimating the number of clusters in a data set is a crucial step in cluster analysis. In this article, motivated by the gap method (Tibshirani, Walther, and Hastie, 2001, Journal of the Royal Statistical Society B63, 411-423), we propose the weighted gap and the difference of difference-weighted (DD-weighted) gap met...

journal_title：Biometrics

authors： Yan M,Ye K

更新日期：2007-12-01 00:00:00

abstract：:Assuming a model of proportional failure rates, Cox (1972) presents a systematic study of the use of covariates in the analysis of life time. The treatment of tied observations is a particularly troublesome point in both theory and application. It appears that grouping rather than discrete time is the right way to han...

journal_title：Biometrics

authors： Thompson WA Jr

更新日期：1977-09-01 00:00:00

abstract：:A life table estimates probabilities of surviving and of dying as well as death rates, as these would apply in a stationary population with the same underlying continuous mortality curve as the observed population. We have derived approximations to the probability of surviving that require no iteration, do not depend ...

journal_title：Biometrics

authors： Keyfitz N,Frauenthal J

更新日期：1975-12-01 00:00:00

abstract：:We consider Bayesian methodology for comparing two or more unlabeled point sets. Application of the technique to a set of steroid molecules illustrates its potential utility involving the comparison of molecules in chemoinformatics and bioinformatics. We initially match a pair of molecules, where one molecule is regar...

journal_title：Biometrics

authors： Dryden IL,Hirst JD,Melville JL

更新日期：2007-03-01 00:00:00

abstract：:Alterations in DNA methylation have been linked to the development and progression of many diseases. The bisulfite sequencing technique presents methylation profiles at base resolution. Count data on methylated and unmethylated reads provide information on the methylation level at each CpG site. As more bisulfite sequ...

journal_title：Biometrics

authors： Ji T

更新日期：2019-06-01 00:00:00

abstract：:In the genetic study of complex traits, especially behavior related ones, such as smoking and alcoholism, usually several phenotypic measurements are obtained for the description of the complex trait, but no single measurement can quantify fully the complicated characteristics of the symptom because of our lack of und...

journal_title：Biometrics

authors： Yu K,Wheeler W,Li Q,Bergen AW,Caporaso N,Chatterjee N,Chen J

更新日期：2010-03-01 00:00:00

abstract：:Zhao and Tsiatis (1997) consider the problem of estimation of the distribution of the quality-adjusted lifetime when the chronological survival time is subject to right censoring. The quality-adjusted lifetime is typically defined as a weighted sum of the times spent in certain states up until death or some other fail...

journal_title：Biometrics

authors： van der Laan MJ,Hubbard A

更新日期：1999-06-01 00:00:00