Abstract:
:The use of three periods in the two-treatment crossover design for clinical trials is considered. It is proposed that a series of such trials in a particular therapeutic area may establish the relevance of the crossover design in that area. Treatment sequences to be used in three-period two-treatment trials are discussed. Two possible designs which allow carryover effects to be tested against the within-subject variability are compared. A design involving four treatment sequences is recommended.
journal_name
Biometricsjournal_title
Biometricsauthors
Ebbutt AFsubject
Has Abstractpub_date
1984-03-01 00:00:00pages
219-24issue
1eissn
0006-341Xissn
1541-0420journal_volume
40pub_type
杂志文章相关文献
BIOMETRICS文献大全abstract::The fitting of finite mixture models via the EM algorithm is considered for data which are available only in grouped form and which may also be truncated. A practical example is presented where a mixture of two doubly truncated log-normal distributions is adopted to model the distribution of the volume of red blood ce...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1988-06-01 00:00:00
abstract::A simple method for comparing independent groups of clustered binary data with group-specific covariates is proposed. It is based on the concepts of design effect and effective sample size widely used in sample surveys, and assumes no specific models for the intracluster correlations. It can be implemented using any s...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1992-06-01 00:00:00
abstract::The distance between homologous DNA sequences of two species is proposed to be -1/4 ln[det(P)], where P is the conditional probability matrix specifying the proportions of the various nucleotides in the second sequence, corresponding to each of the four nucleotides in the first sequence. A probability model is describ...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1987-06-01 00:00:00
abstract::We consider the problem of testing for a dose-related effect based on a candidate set of (typically nonlinear) dose-response models using likelihood-ratio tests. For the considered models this reduces to assessing whether the slope parameter in these nonlinear regression models is zero or not. A technical problem is t...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/biom.12563
更新日期:2017-03-01 00:00:00
abstract::In this article, we propose a Bayesian approach to dose-response assessment and the assessment of synergy between two combined agents. We consider the case of an in vitro ovarian cancer research study aimed at investigating the antiproliferative activities of four agents, alone and paired, in two human ovarian cancer ...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.1541-0420.2010.01403.x
更新日期:2010-12-01 00:00:00
abstract::Multipoint linkage analysis is being performed routinely in medical genetic studies to localize disease genes. This likelihood-based method is very computationally intensive. Exact computations are thus formidable for problems with large number of genetic markers and complex pedigrees. This paper proposes a Monte Carl...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1996-12-01 00:00:00
abstract::Cancer population studies based on cancer registry databases are widely conducted to address various research questions. In general, cancer registry databases do not collect information on cause of death. The net survival rate is defined as the survival rate if a subject would not die for any causes other than cancer....
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/biom.12568
更新日期:2017-03-01 00:00:00
abstract::I discuss diagnostic methods for discriminant analysis. The equivalence with linear regression is noted and regression diagnostics are considered. The leverage is a function of the linear discriminant function and the Mahalanobis distance of the observation from the group mean. The distribution of this distance is app...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1997-12-01 00:00:00
abstract::The accuracy of a new diagnostic test is often determined by comparison with a reference test which also has unknown error rates. Maximum likelihood estimation of the error rates of both tests is possible if they are simultaneously applied to two populations with different disease prevalences. The estimation procedure...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1985-12-01 00:00:00
abstract::Using genetic recombination data to make inferences about chiasmata on the tetrad during meiosis is a classic problem dating back to Weinstein's paper in 1936 (Genetics 21, 155-199). In the last few years, Weinstein's methods have been revived and applied to new problems, but a number of important statistical issues r...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.0006-341x.2002.00369.x
更新日期:2002-06-01 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
pub_type: 杂志文章
doi:10.1111/biom.13233
更新日期:2020-12-01 00:00:00
abstract::Logistic regression is a popular tool for risk analysis in medical and population health science. With continuous response data, it is common to create a dichotomous outcome for logistic regression analysis by specifying a threshold for positivity. Fitting a linear regression to the nondichotomized response variable a...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/biom.12007
更新日期:2013-06-01 00:00:00
abstract:SUMMARY:We develop sample size formulas for studies aiming to test mean differences between a treatment and control group when all-or-none nonadherence (noncompliance) and selection bias are expected. Recent work by Fay, Halloran, and Follmann (2007, Biometrics 63, 465-474) addressed the increased variances within grou...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.1541-0420.2008.01114.x
更新日期:2009-06-01 00:00:00
abstract::Capture-recapture models are widely used to estimate demographic parameters of marked populations. Recently, this statistical theory has been extended to modeling dispersal of open populations. Multistate models can be used to estimate movement probabilities among subdivided populations if multiple sites are sampled. ...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.0006-341x.2001.00273.x
更新日期:2001-03-01 00:00:00
abstract::We present an approach for analyzing internal dependencies in counting processes. This covers the case with repeated events on each of a number of individuals, and more generally, the situation where several processes are observed for each individual. We define dynamic covariates, i.e., covariates depending on the pas...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.0006-341X.2004.00227.x
更新日期:2004-09-01 00:00:00
abstract::Jolliffe and Jolliffe (1997, Biometrics 53, 1136-1142) proposed various models for data from an experiment on memory in coal tits. This article describes an alternative model, which fits equally well and which may be simpler to interpret. ...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.0006-341x.1999.00660.x
更新日期:1999-06-01 00:00:00
abstract::A likelihood ratio statistic is proposed for testing goodness of fit with grouped data which are subject to random right censoring. It is shown that, under appropriate conditions, this statistic has an asymptotic chi-square distribution which is non-central under contiguous alternatives. A formula is given for the non...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1978-09-01 00:00:00
abstract::The first part of the article reviews the Data Augmentation algorithm and presents two approximations to the Data Augmentation algorithm for the analysis of missing-data problems: the Poor Man's Data Augmentation algorithm and the Asymptotic Data Augmentation algorithm. These two algorithms are then implemented in the...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1991-12-01 00:00:00
abstract::In most research on smoothing splines the focus has been on estimation, while inference, especially hypothesis testing, has received less attention. By defining design matrices for fixed and random effects and the structure of the covariance matrices of random errors in an appropriate way, the cubic smoothing spline a...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.1541-0420.2010.01537.x
更新日期:2011-09-01 00:00:00
abstract::In this article, we present new methods to analyze data from an experiment using rodent models to investigate the role of p27, an important cell-cycle mediator, in early colon carcinogenesis. The responses modeled here are essentially functions nested within a two-stage hierarchy. Standard functional data analysis lit...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.1541-0420.2007.00846.x
更新日期:2008-03-01 00:00:00
abstract::We propose a generalized linear mixed model to estimate and test marginal effects on titers repeatedly measured by serial dilution assays. The link is log-log and the titer is assumed to follow a gamma distribution. The parameters are estimated by generalized estimating equations. The marginal effects are tested by me...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1998-06-01 00:00:00
abstract::We consider methods for estimating the treatment effect and/or the covariate by treatment interaction effect in a randomized clinical trial under noncompliance with time-to-event outcome. As in Cuzick et al. (2007), assuming that the patient population consists of three (possibly latent) subgroups based on treatment p...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/biom.12472
更新日期:2016-09-01 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
pub_type: 杂志文章
doi:
更新日期:1991-03-01 00:00:00
abstract::Asymptotic confidence bands for generalized nonlinear regression models are developed. These are based on a combination of the S method of Scheffe, together with the delta method which is used to approximate the mean function by a linear combination of the parameters. The approach can be used in any situation where la...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1995-03-01 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
pub_type: 杂志文章
doi:10.1111/j.1541-0420.2011.01714.x
更新日期:2012-09-01 00:00:00
abstract::A nonparametric maximum likelihood procedure is given for estimating the survivor function from right-censored data. It approximates the hazard rate by a simple function such as a spline, with different approximations yielding different estimators. A special case is that proposed by Nelson (1969, Journal of Quality Te...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1986-09-01 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
pub_type: 杂志文章
doi:10.1111/j.0006-341x.2000.01268.x
更新日期:2000-12-01 00:00:00
abstract::Often with data from immunoassays, the concentration-response relationship is nonlinear and intra-assay response variance is heterogeneous. Estimation of the standard curve is usually based on a nonlinear heteroscedastic regression model for concentration-response, where variance is modeled as a function of mean respo...
journal_title:Biometrics
pub_type: 杂志文章
doi:
更新日期:1996-03-01 00:00:00
abstract::In the evaluation of diagnostic accuracy of tests, a gold standard on the disease status is required. However, in many complex diseases, it is impossible or unethical to obtain such a gold standard. If an imperfect standard is used, the estimated accuracy of the tests would be biased. This type of bias is called imper...
journal_title:Biometrics
pub_type: 杂志文章
doi:10.1111/j.1541-0420.2005.00324.x
更新日期:2005-06-01 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
pub_type: 杂志文章
doi:10.1111/j.0006-341x.2000.01047.x
更新日期:2000-12-01 00:00:00