abstract：:I discuss alternatives to the one compartment model, delta Yt = alpha + beta exp(- gamma t). Instead of comparing the one and two compartment models, I derive statistics for testing mixtures of the parameters (beta, gamma) in the one compartment model. I apply the proposed methods to the problem of hydrogen clearance ...

journal_title：Statistics in medicine

authors： Zelterman D

更新日期：1989-08-01 00:00:00

abstract：:Although estimation and confidence intervals have become popular alternatives to hypothesis testing and p-values, statisticians usually determine sample sizes for randomized clinical trials by controlling the power of a statistical test at an appropriate alternative, even those statisticians who recommend the use of c...

journal_title：Statistics in medicine

authors： Bristol DR

更新日期：1989-07-01 00:00:00

abstract：:Day and Walter derived methods of joint maximum likelihood estimation for the sojourn time distribution and the false negative rate for a screening programme. Their methods are not directly applicable to a programme which uses alternate screening by two modalities whose sojourn times and false negative rates will diff...

journal_title：Statistics in medicine

authors： Alexander FE

更新日期：1989-06-01 00:00:00

abstract：:We examine Goodman and Kruskal's lambda using Efron's approach to regression and analysis of variance (ANOVA) for zero-one outcome data. For a binary response cross-classified by a single nominal predictor, we present a computationally simple ANOVA table in which lambda is analogous to Pearson's R-square. We character...

journal_title：Statistics in medicine

authors： Makuch RW,Rosenberg PS,Scott G

更新日期：1989-05-01 00:00:00

abstract：:A model is developed to estimate the effect of covariate imbalance on the size of a test of treatment efficacy in randomized clinical trials comparing two treatments when dispersion parameters are known. It is concluded that tests of homogeneity on the covariates should not be performed, that covariate imbalance is ju...

journal_title：Statistics in medicine

authors： Senn SJ

更新日期：1989-04-01 00:00:00

abstract：:The primary purpose of a disease surveillance system is to provide data for the detection of changes in the incidence of the disease. Methods for the analysis of data from surveillance systems are reviewed. A new procedure is proposed for use when the system includes geographically dispersed reporting units, such as h...

journal_title：Statistics in medicine

authors： Raubertas RF

更新日期：1989-03-01 00:00:00

abstract：:We applied a two-stage random effects model to pulmonary function data from 31 sarcoidosis patients to illustrate its usefulness in analysing unbalanced longitudinal data. For the first stage, repeated measurements of percentage of predicted forced vital capacity (FVC%) from an individual were modelled as a function o...

journal_title：Statistics in medicine

authors： Vacek PM,Mickey RM,Bell DY

更新日期：1989-02-01 00:00:00

abstract：:Recent studies have indicated variation in the infectivity beta of HIV among heterosexual couples. We represent this heterogeneity by modelling beta as a random variable. Using data on the number of contacts and seroconversion of couples, we fit the model by maximum-likelihood estimation with a beta distribution and a...

journal_title：Statistics in medicine

authors： Wiley JA,Herschkorn SJ,Padian NS

更新日期：1989-01-01 00:00:00

abstract：:An observed confidence distribution is proposed as a measure of strength of evidence for practically equivalent efficacies of two treatments. The concept is independent of prior opinions about relevant sizes of a difference in efficacy. It also avoids retrospective power calculations for trials with missed recruitment...

journal_title：Statistics in medicine

authors： Mau J

更新日期：1988-12-01 00:00:00

abstract：:Although hypertension is regarded as a causal factor for coronary heart disease (CHD) a reduction in the risk of CHD as a result of lowering blood pressure in mild hypertension could not be demonstrated. This conclusion is based on an overview analysis of all published randomized trials in mild hypertension, including...

journal_title：Statistics in medicine

authors： Holme I

更新日期：1988-11-01 00:00:00

abstract：:The Rvachev-Baroyan-Longini model is a space-time predictive model of the spread of influenza epidemics. It has been applied to 128 cities of the USSR, and more recently, to forecasting the spread of the pandemic of 1968-1969 throughout 52 large cities. It is a deterministic, mass-action, space and time continuous mod...

journal_title：Statistics in medicine

authors： Flahault A,Letrait S,Blin P,Hazout S,Ménarés J,Valleron AJ

更新日期：1988-11-01 00:00:00

abstract：:This paper presents a statistically optimal exact hypothesis testing procedure for detecting changes in sales adjusted adverse drug reaction (ADR) rates between historical and current periods, with a computer program that implements this test appended. We provide discussions and illustrations on how to monitor ADR rat...

journal_title：Statistics in medicine

authors： Norwood PK,Sampson AR

更新日期：1988-10-01 00:00:00

abstract：:This paper presents a statistical analysis of treatment effects in 24-hour ambulatory blood pressure recordings. The statistical models account for circadian rhythms, subject effects, and the effects of treatment with drugs or relaxation therapy. In view of the heterogeneity of the subjects, we fit a separate linear m...

journal_title：Statistics in medicine

authors： Marler MR,Jacob RG,Lehoczky JP,Shapiro AP

更新日期：1988-06-01 00:00:00

abstract：:Standard methods for analysing survival data or case-control data normally concern factors affecting a subject as a whole. However, in a study of a condition that might develop in one or both of a pair of bodily organs information on response and on covariates may be available for each separately. This information can...

journal_title：Statistics in medicine

authors： Whitehead J,Dorse C

更新日期：1988-05-01 00:00:00

abstract：:The serial dilution assay (for example, an in vitro antimicrobic susceptibility test or a serum antibody titer assay) is an important technique in biomedical research. The structure of the experiment forces grouping of the threshold concentrations into intervals. Statistical methods to analyse threshold concentrations...

journal_title：Statistics in medicine

authors： Hamilton MA,Rinaldi MG

更新日期：1988-04-01 00:00:00

abstract：:This paper presents a general approach for simultaneously assessing, from serial data, diagnostic consistency, interrater reliability and incidence of a strictly progressive disease. Observed data are viewed as incomplete: diagnostic errors are not distinguished from true diagnoses. We introduce a broad class of model...

journal_title：Statistics in medicine

authors： Espeland MA,Murphy WC,Leverett DH

更新日期：1988-03-01 00:00:00

abstract：:Lung function tests are used both clinically, in assessing disease, and epidemiologically, in identifying those factors which influence the growth and aging process of the lungs. The user must beware of several common pitfalls in the use of these tests, however. First, the commonly used tests of lung function can only...

journal_title：Statistics in medicine

authors： Buist AS,Vollmer WM

更新日期：1988-01-01 00:00:00

abstract：:Incomplete and unbalanced multivariate data often arise in longitudinal studies due to missing or unequally-timed repeated measurements and/or the presence of time-varying covariates. A general approach to analysing such data is through maximum likelihood analysis using a linear model for the expected responses, and s...

journal_title：Statistics in medicine

authors： Schluchter MD

更新日期：1988-01-01 00:00:00

abstract：:We consider several sources of heterogeneity in a clinical trial with patients' survival time as the main response criterion: differences in prognosis which can be attributed to a latent or ignored prognostic factor; differences in treatment efficacy in subgroups of patients, and differences in treatment combinations ...

journal_title：Statistics in medicine

authors： Schumacher M,Olschewski M,Schmoor C

更新日期：1987-10-01 00:00:00

abstract：:We present a method to determine the number of subjects, k, and number of repeated measurements, n, that minimize the overall cost of conducting a reliability study, while providing acceptable power for tests of hypotheses concerning the reliability coefficient rho. Tables showing optimal choices of k and n under vari...

journal_title：Statistics in medicine

authors： Eliasziw M,Donner A

更新日期：1987-09-01 00:00:00

abstract：:A number of variance formulae for the attributable fraction have been presented, but none is consistent in sparse data, such as found in individually matched case-control studies. This paper employs Mantel-Haenszel estimation to derive variance estimators for attributable fractions that are dually consistent, that is,...

journal_title：Statistics in medicine

authors： Greenland S

更新日期：1987-09-01 00:00:00

abstract：:This paper discusses and compares several estimators of mean rate of change in unbalanced longitudinal data based on a model with randomly distributed regression coefficients across individuals. The estimators are unweighted and weighted means of these coefficients. The paper also evaluates commonly used variance esti...

journal_title：Statistics in medicine

authors： Palta M,Cook T

更新日期：1987-07-01 00:00:00

abstract：:Dependence between observations on a dichotomous variable renders invalid the usual chi-square tests of independence and inflates the variances of parameter estimates. Such a situation occurs, for example, when subjects consist of members of the same family or with repeated observations on the same person. In this pap...

journal_title：Statistics in medicine

authors： Donald A,Donner A

更新日期：1987-06-01 00:00:00

abstract：:Evaluating treatment effects within different subsets of patients is a common practice in the analysis of individual randomized clinical trials. Such analyses are limited, however, by the number of patients available. Overviews, by providing evidence based on large numbers of patients, can be useful for overcoming the...

journal_title：Statistics in medicine

authors： Gelber RD,Goldhirsch A

更新日期：1987-04-01 00:00:00

abstract：:When asking 'what is known' about a drug or therapy or program at any time, both researchers and practitioners often confront more than a single study. Facing a variety of findings, where conflicts may outweigh agreement, how can a reviewer constructively approach the task? In this discussion, I will outline some ques...

journal_title：Statistics in medicine

authors： Light RJ

更新日期：1987-04-01 00:00:00

abstract：:Previous work on the consequences of regression to the mean for the interpretation of responses to treatment is extended to the situation where the response measured is the proportional change in some variable. Methods for correcting for the bias are discussed. ...

journal_title：Statistics in medicine

authors： Curnow RN

更新日期：1987-03-01 00:00:00

abstract：:One may encounter the application of the two independent samples t-test to ordinal scaled data (for example, data that assume only the values 0, 1, 2, 3) from small samples. This situation clearly violates the underlying normality assumption for the t-test and one cannot appeal to large sample theory for validity. In ...

journal_title：Statistics in medicine

authors： Heeren T,D'Agostino R

更新日期：1987-01-01 00:00:00

abstract：:The two tailed Fisher's exact P value is extremely sensitive to small perturbations in 2 x 2 contingency tables. An example indicates that a 1 per cent increase in the denominator of one treatment group results in a 32 per cent drop in the exact P value, but a mere 0.1 per cent decrease in the treatment success rate. ...

journal_title：Statistics in medicine

authors： Dupont WD

更新日期：1986-11-01 00:00:00

abstract：:In this paper the following problem of clinical research is explored. Several potential new treatments are available for use against a certain disease. These are evaluated in a series of pilot studies which will constitute phase II clinical trials. The most promising will then be compared with a standard treatment in ...

journal_title：Statistics in medicine

authors： Whitehead J

更新日期：1986-09-01 00:00:00

abstract：:This paper describes statistical procedures for use in an experiment that compares two handwashing protocols. The evaluation of a handwashing protocol entails collection of the wash effluent. Colony counts for the effluent reflect the number of flora removed by the wash protocol. The analysis aims to formulate and est...

journal_title：Statistics in medicine

authors： Le CT

更新日期：1986-07-01 00:00:00

abstract：:A calibration line is used to define the relationship between a new clinical technique and a standard in vitro laboratory methodology. Discrimination intervals quantify the reliability of inverse estimates obtained from the calibration line. Applied to transcutaneous PCO2 monitoring, a new in vivo measurement, discrim...

journal_title：Statistics in medicine

authors： Kost GJ

更新日期：1986-07-01 00:00:00

abstract：:A trial of Duchenne muscular dystrophy involved tracking boys of all ages through a one-year baseline period, followed by a one-year trial of leucine versus placebo treatment. In this paper we develop a model for a total-muscle-strength score that uses the data of the extended baseline period in the evaluation of the ...

journal_title：Statistics in medicine

authors： Madsen KS,Miller JP,Province MA

更新日期：1986-05-01 00:00:00

abstract：:A statistical analysis is presented of the intensities of admissions to psychiatric hospitals among women in Denmark who either gave birth to a child in the year 1975 or had an induced abortion in the same year. The models used are time-continuous Markov and semi-Markov processes, and the methods employed include non-...

journal_title：Statistics in medicine

authors： Andersen PK,Rasmussen NK

更新日期：1986-05-01 00:00:00

abstract：:Estimates of analyte concentrations, obtained by immunoassay, have error distributions which are generally underestimated. Better estimates, which take into account the distribution of the response metameter of the calibration curve and uncertainties associated with the location of the fitted curve, have been obtained...

journal_title：Statistics in medicine

authors： Kay C,Nix AB,Kemp KW,Rowlands RJ,Richards G,Groom GV,Griffiths K,Wilson DW

更新日期：1986-03-01 00:00:00

abstract：:Korn and Whittemore have presented methods for analyzing longitudinal data where the number of observations per individual is large relative to the number of variables considered for each subject. However, this is often not the case in epidemiologic studies, since one usually collects data at relatively few time point...

journal_title：Statistics in medicine

authors： Rosner B,Muñoz A,Tager I,Speizer F,Weiss S

更新日期：1985-10-01 00:00:00

abstract：:We discuss the use of the trichotomous logistic model to discriminate between patients with gastrointestinal (GI) cancer, patients with benign GI disease and 'normal' subjects, using symptoms and the concentrations of some serum proteins that are potentially indicative of malignancy as covariates. A parsimonious model...

journal_title：Statistics in medicine

authors： Marshall RJ,Chisholm EM

更新日期：1985-07-01 00:00:00

abstract：:We describe the usual statistical concepts and consequent appropriate simulations of a prospective study for the simple case of a single risk variable and an assumed logistic model. We examine the simulations of Lilienfeld and Pyne, and show that they are seriously flawed. Contrary to those authors' claims, the estima...

journal_title：Statistics in medicine

authors： Halperin M,Abbott RD,Blackwelder WC,Jacobowitz R,Lan KK,Verter JI,Wedel H

更新日期：1985-04-01 00:00:00

abstract：:A method has been developed for simultaneously comparing the usefulness of many treatments of established value for symptomatic medical conditions. Medical assessment of outcome is not employed. Instead patients are required to assess treatments prescribed during the course of ordinary general practice rather than und...

journal_title：Statistics in medicine

authors： Charlton JR,D'Souza MF,Tooley M,Silver R

更新日期：1985-01-01 00:00:00

abstract：:Clinical trials of treatments for rare or fatal diseases must often use historical rather than randomized concurrent controls. Randomized trials may not be possible if (1) the number of patients available is quite small, (2) ethical considerations discourage the assignment of patients to control treatments known to be...

journal_title：Statistics in medicine

authors： Hoehler FK,Mantel N,Gehan E,Kahana E,Alter M

更新日期：1984-07-01 00:00:00

abstract：:This paper examines several methods for deriving standardized morbidity ratios (SMR) and attributable fraction (attributable risk percentage) estimates. We show that some of the proposed methods will, in general, produce biased estimators, although the low variance of certain estimators sometimes compensates for their...

journal_title：Statistics in medicine

authors： Greenland S

更新日期：1984-04-01 00:00:00