A comparison of several point estimators of the odds ratio in a single 2 x 2 contingency table.

abstract：:A multiple toxicity model for the quantal response of organisms is constructed based on an existing bivariate theory. The main assumption is that the tolerances follow a multivariate normal distribution function. However, any monotone tolerance distribution can be applied by mapping the integration region in the n-dim...

journal_title：Biometrics

authors： Christensen ER,Chen CY

更新日期：1985-09-01 00:00:00

abstract：:The risks of conception, due to sexual intercourse at various times before and after the periovulatory rise in the woman's basal body temperature, are evaluated. In general, the risk is small nine or more days before, and two or more days after, the first day of elevated temperature. The model for the conception proba...

journal_title：Biometrics

authors： Royston JP

更新日期：1982-06-01 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：: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：:In this article, we investigate clustering methods for multilevel functional data, which consist of repeated random functions observed for a large number of units (e.g., genes) at multiple subunits (e.g., bacteria types). To describe the within- and between variability induced by the hierarchical structure in the data...

journal_title：Biometrics

authors： Serban N,Jiang H

更新日期：2012-09-01 00:00:00

abstract：:In this paper alternative methods for estimating the relative potency, its confidence intervals, and testing for proportionality are developed for multivariate bioassays. The test and estimate are based on the smaller characteristic root and the corresponding characteristic vector of a 2 X 2 matrix. The same idea is a...

journal_title：Biometrics

authors： Srivastava MS

更新日期：1986-03-01 00:00:00

abstract：:In the field of cardio-thoracic surgery, valve function is monitored over time after surgery. The motivation for our research comes from a study which includes patients who received a human tissue valve in the aortic position. These patients are followed prospectively over time by standardized echocardiographic assess...

journal_title：Biometrics

authors： Andrinopoulou ER,Eilers PHC,Takkenberg JJM,Rizopoulos D

更新日期：2018-06-01 00:00:00

abstract：:Likelihood ratio tests for parameters estimated assuming normally distributed errors are examined under a variety of homoscedastic and heteroscedastic variance assumptions. It is assumed that gamma ij, the jth observation from the ith population, is distributed as N[mu(chi ij, beta i), (sigma i mu(chi ij, beta i)theta...

journal_title：Biometrics

authors： Kimura DK

更新日期：1990-09-01 00:00:00

abstract：SUMMARY:Recently, median regression models have received increasing attention. When continuous responses follow a distribution that is quite different from a normal distribution, usual mean regression models may fail to produce efficient estimators whereas median regression models may perform satisfactorily. In this ar...

journal_title：Biometrics

authors： Yi GY,He W

更新日期：2009-06-01 00:00:00

abstract：:Brain evoked potential (EP) data consist of a true response ("signal") and random background activity ("noise"), which are observed over repeated stimulus presentations ("trials"). A signal that changes slowly from trial to trial can be estimated by smoothing across trials and over time within trials. We present a met...

journal_title：Biometrics

authors： Raz J,Turetsky B,Fein G

更新日期：1989-09-01 00:00:00

abstract：:As ultra high-dimensional longitudinal data are becoming ever more apparent in fields such as public health and bioinformatics, developing flexible methods with a sparse model is of high interest. In this setting, the dimension of the covariates can potentially grow exponentially as ...

journal_title：Biometrics

authors： Green B,Lian H,Yu Y,Zu T

更新日期：2020-08-04 00:00:00

abstract：:For patients with chronic myelogenous leukemia (CML), the effect of elevated blood levels of adenosine deaminase (ADA) is studied as a marker for transitions from stable disease to blast crisis and then to death. Data in the form of snapshots over time, with day, state of disease, and ADA level, are analyzed for 55 pa...

journal_title：Biometrics

authors： Klein JP,Klotz JH,Grever MR

更新日期：1984-12-01 00:00:00

abstract：:Motivated by the spatial modeling of aberrant crypt foci (ACF) in colon carcinogenesis, we consider binary data with probabilities modeled as the sum of a nonparametric mean plus a latent Gaussian spatial process that accounts for short-range dependencies. The mean is modeled in a general way using regression splines....

journal_title：Biometrics

authors： Apanasovich TV,Ruppert D,Lupton JR,Popovic N,Turner ND,Chapkin RS,Carroll RJ

更新日期：2008-06-01 00:00:00

abstract：:This article demonstrates semiparametric maximum likelihood estimation of a nonlinear growth model for fish lengths using imprecisely measured ages. Data on the species corvina reina, found in the Gulf of Nicoya, Costa Rica, consist of lengths and imprecise ages for 168 fish and precise ages for a subset of 16 fish. T...

journal_title：Biometrics

authors： Suh EY,Schafer DW

更新日期：2002-06-01 00:00:00

abstract：:Currently, the design of group sequential clinical trials requires choosing among several distinct design categories, design scales, and strategies for determining stopping rules. This approach can limit the design selection process so that clinical issues are not fully addressed. This paper describes a family of desi...

journal_title：Biometrics

authors： Kittelson JM,Emerson SS

更新日期：1999-09-01 00:00:00

abstract：:Vaccine-induced protection may not be homogeneous across individuals. It is possible that a vaccine gives complete protection for a portion of individuals, while the rest acquire only incomplete (leaky) protection of varying magnitude. If vaccine efficacy is estimated under wrong assumptions about such individual leve...

journal_title：Biometrics

authors： Mehtälä J,Dagan R,Auranen K

更新日期：2016-09-01 00:00:00

abstract：:A stochastic model is presented for the analysis of incomplete repeated-measures experiments. The general linear model is used to relate the response measures to other variables which are thought to account for inherent variation; an autoregressive moving average (ARMA) time series representation is used to model dist...

journal_title：Biometrics

authors： Rochon J,Helms RW

更新日期：1989-03-01 00:00:00

abstract：:Certain probability models sometimes provide poor descriptions when fitted to data by maximum likelihood. We examine one such model for the survival of wild animals, which is fitted to two sets of data. When the model behaves poorly, its expected information matrix, evaluated at the maximum likelihood estimate of para...

journal_title：Biometrics

authors： Catchpole EA,Kgosi PM,Morgan BJ

更新日期：2001-09-01 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：:Whenever inference for variance components is required, the choice between one-sided and two-sided tests is crucial. This choice is usually driven by whether or not negative variance components are permitted. For two-sided tests, classical inferential procedures can be followed, based on likelihood ratios, score stati...

journal_title：Biometrics

authors： Verbeke G,Molenberghs G

更新日期：2003-06-01 00:00:00

abstract：:Matched case-control designs are commonly used in epidemiologic studies for increased efficiency. These designs have recently been introduced to the setting of modern imaging and genomic studies, which are characterized by high-dimensional covariates. However, appropriate statistical analyses that adjust for the match...

journal_title：Biometrics

authors： Qian J,Payabvash S,Kemmling A,Lev MH,Schwamm LH,Betensky RA

更新日期：2014-03-01 00:00:00

abstract：:Consider two independent random variables X and Y. The functional R = Pr(X less than Y) [or gamma = Pr(X less than Y) - Pr(Y less than X)] is of practical importance in many situations, including clinical trials, genetics, and reliability. In this paper several approaches to estimation of gamma when X and Y are presen...

journal_title：Biometrics

authors： Simonoff JS,Hochberg Y,Reiser B

更新日期：1986-12-01 00:00:00

abstract：:This paper describes methodology for analyzing data from cluster randomized trials with count outcomes, taking indirect effects as well spatial effects into account. Indirect effects are modeled using a novel application of a measure of depth within the intervention arm. Both direct and indirect effects can be estimat...

journal_title：Biometrics

authors： Anaya-Izquierdo K,Alexander N

更新日期：2020-06-18 00:00:00

abstract：:In biomedical cohort studies for assessing the association between an outcome variable and a set of covariates, usually, some covariates can only be measured on a subgroup of study subjects. An important design question is-which subjects to select into the subgroup to increase statistical efficiency. When the outcome ...

journal_title：Biometrics

authors： Wang L,Williams ML,Chen Y,Chen J

更新日期：2020-03-01 00:00:00

abstract：:The variogram is a standard tool in the analysis of spatial data, and its shape provides useful information on the form of spatial correlation that may be present. However, it is also useful to be able to assess the evidence for the presence of any spatial correlation. A method of doing this, based on an assessment of...

journal_title：Biometrics

authors： Diblasi A,Bowman AW

更新日期：2001-03-01 00:00:00

abstract：:This note provides a discussion on the manuscript by Wang et al. (2005) who aim to robustify inference for longitudinal data analysis by replacing the ordinary generalized estimating function with an influence-bounded, possibly biased, version. To adjust for the bias of the ensuing robust estimator, the authors provid...

journal_title：Biometrics

authors： Lunardon N,Menardi G

更新日期：2020-09-01 00:00:00

abstract：:We suggest an estimator for the proportional odds cumulative incidence model for competing risks data. The key advantage of this model is that the regression parameters have the simple and useful odds ratio interpretation. The model has been considered by many authors, but it is rarely used in practice due to the lack...

journal_title：Biometrics

authors： Eriksson F,Li J,Scheike T,Zhang MJ

更新日期：2015-09-01 00:00:00

abstract：:In clinical trials and other investigations of survival time, information is often available on a time-dependent event other than survival. An example of such an auxiliary event in cancer studies is objective progression of disease. While some patients expire without experiencing objective disease progression, others ...

journal_title：Biometrics

authors： Lagakos SW

更新日期：1976-09-01 00:00:00

abstract：:Multiple outcomes are often used to properly characterize an effect of interest. This paper proposes a latent variable model for the situation where repeated measures over time are obtained on each outcome. These outcomes are assumed to measure an underlying quantity of main interest from different perspectives. We re...

journal_title：Biometrics

authors： Roy J,Lin X

更新日期：2000-12-01 00:00:00

abstract：:We consider a two-sample problem where data come from symmetric distributions. Usual two-sample data with only magnitudes recorded, arising from case-control studies or logistic discriminant analyses, may constitute a symmetric two-sample problem. We propose a semiparametric model such that, in addition to symmetry, t...

journal_title：Biometrics

authors： Li M,Diao G,Qin J

更新日期：2020-12-01 00:00:00