摘要:

AbstractEstimating the diagnostic efficiency of marker tests on the basis of the training set is an intricate problem of discriminant analysis for which no analytical solution exists. The paper outline the problem, describes various popular estimation procedures and presents the results of computer simulations comparing the estimators with respect to both bias and variance.

ISSN:0323-3847    

DOI:10.1002/bimj.4710280802

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAn algorithm that searches for optimal block designs when block effects are random is described. Some situations in which such an algorithm will prove useful are considered. An illustrative example and some discussion are given.

ISSN:0323-3847    

DOI:10.1002/bimj.4710280803

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractScores for the analysis of distinct failure time data using ranks are modified to deal with tied failure times or grouped data. Approximate techniques for inference for regression parameters are considered for ‘proportional odds’ and ‘proportional hazards’ survival data involving tied failures or grouped data. An illustration is given involving a two sample

ISSN:0323-3847    

DOI:10.1002/bimj.4710280804

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractStarting from anr×rcontingency table derived from ordinal pre‐ and post treatment observations, the traditional Bowker symmetry test is suggested to be replaced by one of the following alternatives (1) a globals test of general improvement, (2) a set of simultaneous symmetry tests of differential improvement without assuming general improvement underH0and (3) a set of simultaneous symmetry tests beyond assuming general improvement underH0. The tests are illustrated by a bivariate example of observing neuroticism and introversion binarily (+, ‐) before and after Rogerian psychotherapy in a sample of cli

ISSN:0323-3847    

DOI:10.1002/bimj.4710280805

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710280806

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractIn this note we present improved Bonferroni type inequalities for the union of a set of nonexchangeable events. These new bounds are stronger than or equivalent with the bounds proposed by KOUNIAS (1968), HUNTER (1976), MARGOLIN&MAURER (1976), GALAMBOS (1977) and by Mǎrgǎkritescu (1983). In the particular case of the exchangeable events, the bounds given by SOBEL&UPPULURI (1972) can be derived. A generalization in terms of a partition of {1, 2, …,n} is also establis

ISSN:0323-3847    

DOI:10.1002/bimj.4710280807

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710280808

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA derivation of the maximum likelihood ratio test for testing no outliers in regression models is given using the method of WETHERILL (1981, pp. 106–107) for estimating the regression parameters. This method is essentially similar to the one outlined in BARNETT and LEWIS (1978, p. 263), although by our detailed derivation it is easier to see that the maximum likelihood estimate of θ of model (3) under the hypothesis that theithobservation in an outlier is the same as that obtained from model (1) when theithobservation is remov

ISSN:0323-3847    

DOI:10.1002/bimj.4710280809

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA perennial problem in statistics is the determination of biases, variances and covariances for functions of random variablesX1,X2, …,Xnwhich themselves have a known distribution. A common approach is through equations based upon Taylor series approximations but a “point evaluation” method may sometimes be a useful alternative. This involves approximating the multivariate distribution of theXvariables by the 2npoints given byX1=μ1±1,X2= μ2±2, …,Xn= = μnμn, where μiis the mean and σithe standard deviation ofXi, with appropriate point weights. An advantage over the Taylor series approach is that function derivatives do not have to be explicitely calculated. The point evaluation method is particularly useful in cases where theXvariables are uncorrelated. Then the evaluation of the 2npoints can be replaced by the evaluation of 2npoints. The point evaluation method is illustrated with powers of a normally distributed variable, and with estimation of gene frequencies from ABO blood gr

ISSN:0323-3847    

DOI:10.1002/bimj.4710280810

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractConditional multivariate normal density functions are used to construct conditional quadratic discriminant functions that adjust for covariate differences between disease groups. An expected actual error rate for the conditional discriminant function is defined. The purpose of this paper is to use the conditional quadratic discriminant function and its misolassification error rate in order to help determine if a set of discriminators is a good biological marker for disease screening. The conditional quadratic discriminant analysis is illustrated using data from two alcoholism classification problems. It is shown how the discriminant functions can identify a set of variables that can be used as biological markers.

ISSN:0323-3847    

DOI:10.1002/bimj.4710280811

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY