摘要:

AbstractThe model considered in this article is the two‐factor nested unbalanced variance component model:forp= 1, 2, …,P;q= 1, 2, …,Qp; andr= 1, 2, …,Rpq. The random variablesYpqrare observable. The constant μ is an unknown parameter, andAp,BpqandCpqrare (unobservable) normal and independently distributed random variables with zero means and finite variances σ2A, σ2B, and σ2C, respectively. Approximate confidence intervals on ϱAand ϱBusing unweighted means are derived, whereThe performance of these approximate confidence intervals are evaluated using computer simulation. The simulated results indicate that these proposed confidence intervals perform satisfactorily and can be used in app

ISSN:0323-3847    

DOI:10.1002/bimj.4710340302

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractExperiments consisting of several doses of a test agent and a zero dose control are often conducted to evaluate the effect of a compound on the response of interest. TUKEY et al. (1985) proposed a trend test procedure which uses the minimump‐value from three candidate dose scalings as a sensitive means for detecting a trend in response with increasing dose. Trend is defined here as a progressiveness, either increasing or decreasing, in response with increasing dose of the test agent. In this paper, we take a closer look at the procedure's inflated type I error rate and propose an adjustment based on the multivariatet‐distribution which preserves the nominal significance level. Application of the adjusted trend test to a number of real data sets indicates that its performance is similar to that observed with Bartholomew's and Williams' tests. An evaluation of these three tests also was conducted on simulated data using an apparently novel approach which takes into account the underlying dosage regimen to genrate the alternative hypotheses for a broad range of dose response relations. The simulation results indicates that the adjusted trend test is overall more powerful than its two competitors, although there are circumstances where each procedure appears superior. This broad‐based power exhibited in both real and simulated settings makes the adjusted trend test an attractive app

ISSN:0323-3847    

DOI:10.1002/bimj.4710340303

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractSeven procedures of multiple comparisons: Tukey, Scheffé, Bonferroni, Studentized Maximum Modulus, Duncan, Newman‐Keuls andFare compared with respect to the probability of the correct decision. Monte Carlo simulation shows that there is no the best procedure.AMS 1985 Subject Classification: 62 J

ISSN:0323-3847    

DOI:10.1002/bimj.4710340304

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe present paper deals with the estimation of design and genetic components of variance based on full double crosses and partial tetra‐allel crosses. We have presented the explicit experissions for the symmetric sums estimators of design components of variance based on Hinkelmann's model. Consequently we have also presented explicitly the genetic components of variance based on full double crosses and partial tetra‐allel crosses. The procedure is also illustrated with the help of a hypothetical d

ISSN:0323-3847    

DOI:10.1002/bimj.4710340305

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this paper we consider the competing risks model where the risks may not be independent. We assume both fixed and random censoring. The random censoring mechanism could have either a parametric or a non‐parametric form. The life distributions and the parametric censoring distribution considered are exponential or Weibull. The expressions for the asymptotic confidence intervals for various parameters of interest under different models, using the estimated Fisher information matrix and parametric bootstrap techniques have been derived. Monte Carlo simulation studies for some of these cases have been carried ou

ISSN:0323-3847    

DOI:10.1002/bimj.4710340306

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractRanked set sampling is a method which may be used to increase the efficiency of the estimator of the mean of a population. Ranked set sampling with size biased probability of selection (i.e., the items are selected with probability proportion to its size) is combined with the line intercept method to increase the efficency of estimating cover, density and total amount of some variable of interest (e.g. biomass). A two‐stage sampling plan is suggested with line intercept sampling in the first stage. Simple random sampling and ranked set sampling are compared in the second stage to show that the unbiased estimators of density, cover and total amount of some variable of interest based on ranked set sampling have smaller variances than the usual unbiased estimator based on simple random sampling. Efficiency is increased by reducing the number of items which are measured on a transect or by increasing the number of independent transects utilized in a study area. An application procedure is given for estimation of coverage, density and number of stems of mountain mahogany (Cercocarpus montanus) in a study area east of Laramie, Wyomin

ISSN:0323-3847    

DOI:10.1002/bimj.4710340307

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper is concerned with testing for umbrella alternatives in ak‐sample location problem when the underlying populations have possibly different shapes. Following CHEN and WOLFE (1990b), rank‐based modifications of the HETTMANSPERGER‐NORTON (1987) tests are considered for both the settings where the peak of the umbrella is known and where it is unknown. The proposed procedures are exactly distribution‐free when the continuous populations are identical with any shape. Moreover, the modified test for peak‐known umbrella alternatives remains asymptotically distribution‐free when the continuous populations are assumed to be symmetric, even if they differ in shapes. Comparative results of a Monte Carlo study ar

ISSN:0323-3847    

DOI:10.1002/bimj.4710340308

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractFor cross‐over trials with the assumption that the within‐subject errors follow an AR(1) process, we propose a method, which is simple to compute, to obtain the generalized least squares estimates. The computation is easily implemented on any software that handles matrix manipulati

ISSN:0323-3847    

DOI:10.1002/bimj.4710340309

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractCOCHRAN (1953) and BARTCH (1957) gave formulae for the magnitude of the sample size (n) ensuring the validity of the limiting normal distribution of the sample meanx(n) obtained from a non‐normal distribution with marked asymmetry and kurtosis.These formulae have been checked empirically in this paper using (a) simulated data with given asymmetry and kurtosis and (b) real data gathered from a coronary heart disease study. We find that our results are in general agreement with Bartch's formula. However, in a number of cases, the asymptotic normal distribution is attained for smaller sample size than that required by Bartch's formul

ISSN:0323-3847    

DOI:10.1002/bimj.4710340310

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710340311

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY