摘要:

AbstractConfidence intervals and tests of hypotheses on variance components are required in studies that employ a random effects design. The unbalanced random two‐fold nested design is considered in this paper and confidence intervals are proposed for the variance components σ2/A and σ2/B. Computer simulation is used to show that even in very unbalanced designs, these intervals generally maintain the stated confidence coefficient. The hypothesis test for σ2/A based on the lower bound of the recommended confidence interval is shown to be better than previously proposed approximate t

ISSN:0323-3847    

DOI:10.1002/bimj.4710340402

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA statistical goodness‐of‐fit test, based on representing the sample observations by linked vectors, is developed. The direction and the length of the linked vectors are defined as functions of the expected values of the order statistics and sample order statistics, respectively. The underlying method can be used to test distributional assumptions for any location‐scale family. A test statisticQnis introduced and some of its properties are studied. It is shown that the proposed test can be generalized to test if two or more independent samples come from the same distribution. The test procedure provides a graphical method of identifying the true distribution when the null hypothesis is rej

ISSN:0323-3847    

DOI:10.1002/bimj.4710340403

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractBoth the Bionomial and Poisson distributions are employed in this study to compute approximate powers for goodness‐of‐fit test statistics. The procedure adopted involves simulating 1000 samples from each of these distributions. These samples are then employed to compute both the randomized nominal critical values and estimated powers. The type I error rates returned from the use of the randomized critical levelsCα fall within the acceptable regions. We illustrate the use of the procedure with the Pearson'sX2test statistic and show that this can readily be extended to any of the other well known goodness‐of‐fit test st

ISSN:0323-3847    

DOI:10.1002/bimj.4710340404

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe paper is a first answer to a fundamental critique of epidemiology that has been voiced in a recent book by Immich. Apart from giving an introduction to this important and controversial work, mostly questions of a biostatistical nature are discussed here. A fundamental counter critique from an epidemiological viewpoint is necessary, but is not attempted in this paper.

ISSN:0323-3847    

DOI:10.1002/bimj.4710340405

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractBased on one year of services utilization data in Santa Clara County, we modeled the mental health service system as a time‐continuous Markov process with corresponding Kolmogorov differential equations. The dynamics of the system's operations in that year can be expressed by the results derived from the intensity matrix and the explicit solution of Kolmogorov differential equations. The key problem with the system is linked to its emergency service. An unexpectedly high proportion of patients had a certain period in which they did not receive any services. Most of patients desired more intensive services. Some tentative thoughts about the stabilization of the system are discusse

ISSN:0323-3847    

DOI:10.1002/bimj.4710340406

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe Cox regression model is one of the most widely used models to incorporate covariates. The frequently used partial likelihood estimator of the regression parameter has to be computed iteratively. In this paper we propose a noniterative estimator for the regression parameter and show that under certain conditions it dominates another noniterative estimator derived by Kalbfleish and Prentice. The new estimator is demonstrated on lifetime data of rats having been subject to insult with a carcinogen.

ISSN:0323-3847    

DOI:10.1002/bimj.4710340407

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper is concerned with investigation into the behavior of the likelihood ratio test statisticG2when the alternative hypothesisM(QQ) is the true model. Exact moments ofG2are computed empirically and three approximations are considered for approximating the non‐null distribution ofG2. Our results show that the two parameter gamma distribution provides a closer approximation to the exact powers ofG2. A randomized procedure was employed to obtain critical values based on 1000 simulated sample

ISSN:0323-3847    

DOI:10.1002/bimj.4710340408

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA nonparametric test to detect a pulse in monthly data is presented. This test is a maximum rank‐sum test. The test statistic can be computed from frequencies or rates. The exact null distribution of the test statistic is tabulated for pulses that last 3, 4, 5, or 6 months. Estimates from a simulation study of the test's type I error rate and power are presented. The statistical modeling of the data is discussed. Several examples are given to illustrate the application of the test and the modeling procedures. Practical matters such as the treatment of tied observations, the effect of unequal lengths in the months, sample‐size calculation, and post‐test power analysis are discussed and illustrated with exa

ISSN:0323-3847    

DOI:10.1002/bimj.4710340409

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractMarkov chain approach has been adopted to forecast sugarcane yield. Two years data (1977–78 and 1978–79) on biometrical characters and yield collected by IASRI, New Delhi under the pilot study on pre‐harvest forecasting of sugarcane yield in Meerut district (U.P.) were utilised for the study. Yield forecasts at 7–8 months after planting (about 2–3 months before harvest) were very close to the observed ones, per cent deviations from observed being 4% in 1978–79 and 2% in 1977–78. This study thus reveals that Markov Chain method can be successfully used in crop yiel

ISSN:0323-3847    

DOI:10.1002/bimj.4710340410

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0323-3847    

DOI:10.1002/bimj.4710340401

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY