摘要:

AbstractIn life‐testing situations under bivariate normality of (X, U), a few smallest or a few largestY‐observations may not be available. Tests for μ = 0 (mean vector) ando= 0 (correlation coefficient) are developed from the availableY‐observations and their concomitantX‐observations. The robustness of these tests to departures from normality is inve

ISSN:0323-3847    

DOI:10.1002/bimj.4710320802

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710320803

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe results of assisting medical diagnosis in bronchial asthma and chronic bronchitis via robust discriminant functions are presented in the paper. The robust discriminant functions are obtained by replacing classical estimates of mean vectors and covariance matrices by their robust equivalents. The new methods were compared with classical ones. These methods resulted in the improvement of automatic diagnosis especially when the “new” data set was classified on the basis of individuals collected earl

ISSN:0323-3847    

DOI:10.1002/bimj.4710320804

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710320805

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper deals with the problem of estimating the individual weights of objects under a biased spring balance weighing design with equal correlations of errors in the model. A lower bound for the variance of each of the estimated weights resulting from this biased spring balance weighing design is obtained and a necessary and sufficient condition for this lower bound to be attained is given. The incidence matrix of a BIB design has been used to construct optimum biased spring balance weighing designs.

ISSN:0323-3847    

DOI:10.1002/bimj.4710320806

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractIn bioassay, where different levels of the stimulus may represent different doses of a drug, the binary response is the death or survival of an individual receiving a specified dose. In such applications, it is common to model the probability of a positive responsePat the stimulus levelxbyP = F(x′β), whereFis a cumulative distribution function and β is a vector of unknown parameters which characterize the response function. The two most popular models used for modelling binary response bioassay involve the probit model [BLISS (1935), FINNEY (1978)], and the logistic model [BERKSON (1944), BROWN (1982)]. However, these models have some limitations. The use of the probit model involves the inverse of the standard normal distribution function, making it rather intractable. The logistic model has a simple form and a closed expression for the inverse distribution function, however, neither the logistic nor the probit can provide a good fit to response functions which are not symmetric or are symmetric but have a steeper or gentler incline in the central probability region. In this paper we introduce a more realistic model for the analysis of quantal response bioassay. The proposed model, which we refer to it as the generalized logistic model, is a family of response curves indexed by shape parametersm1andm2. This family is rich enough to include the probit and logistic models as well as many others as special cases or limiting distributions.In particular, we consider the generalized logistic three parameter model where we assume thatm1=m, mis a positive real number, andm2= 1. We apply this model to various sets of data, comparing the fit results to those obtained previously by other dose‐response curves such as the logistic and probit, and showing that the fit can be improved by using the generalized log

ISSN:0323-3847    

DOI:10.1002/bimj.4710320807

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe usual analysis of quantal response data occurring in diverse fields such as economics, medicine, psychology and toxicology use probit and logit models or their extensions with generalized least squares or the principle of likelihood as the method of statistical inference. The symmetric alternative models lead to practically comparable results and the choice of model or method is determined by considerations of familiarity and computational convenience. Recent attempts at improvement involve larger parametric families of tolerance distributions and employ the method of maximum likelihood in analysis. In this paper we consider models with the tolerance distributions based upon the Tukey‐lambda distributions which are described in terms of their quantile functions. The likelihood methods for fitting the models and testing their adequacies are developed and illustrated using classical data due to BLISS (1935) and ASHFORD and SMITH (1964

ISSN:0323-3847    

DOI:10.1002/bimj.4710320808

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710320809

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe problem of the assessment of bioequivalence between a test formulation (T) and a reference formulation (R) of a drug using a two‐way crossover experiment is considered. To claim bioequivalence between two formulations, it is required by the United States Food and Drug Administration (FDA) to demonstrate that the true ratio of means μT/μRof pharmacokinetic parameters of concern falls within some reasonable limits (e.g., (80%, 120%)) with certain assurance. A commonly used approach is to construct an approximate 90% confidence interval for μT/μRand compare it with (80%, 120%). In this paper, an exact approach according to the FDA's criteria is proposed. The proposed procedure is derived by constructing an exact confidence region (an ellipse) for (μR, μT) and comparing it with the region bounded by μT= 0.8 μRand μT= 1.2 μR. Bioequivalence is concluded if the ellipse is within the crit

ISSN:0323-3847    

DOI:10.1002/bimj.4710320810

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractApredictive P‐valueis proposed to measure the difference between an actual and predicted outcome in assessing the validity of an hypothesized prediction model. The concept is illustrated by applications to multiple regression prediction and to the validation of forecast model

ISSN:0323-3847    

DOI:10.1002/bimj.4710320811

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY