摘要:

The purpose of this paper is to examine the robustness in finite samples of a test for outliers based on the maximum internally studentized residual and the RESET test for functional form misspecification. The effects of incorrect specification on the adequate detection of outliers and the presence of one or more outliers on the rejection frequencies of RESET are analysed. It is found that, ingeneral, the test for outliers does not seem to be robust to functional form misspecification, while the rejection frequencies of RESET can be reduced, sometimes dramatically, in the presence of outliers.

ISSN:0266-4763    

DOI:10.1080/02664769200000038

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

The purpose of this paper is to consider methods which discriminate between 2- and 3-parameter nested alternatives for the gamma, Weibull and log-normal distributions, and to investigate their utility in representing frequency distributions of air pollutant measurements. Monte Carlo experiments are conducted to evaluate the likelihood ratio test, Akaike's information criterion, Schwarz's information criterion, the Chi-square test and the Kolmogorov-Smirnov test. The performance of the tests and criteria depends on the types of nested distributions under consideration, the parametric values of the parent distributions, the confidence levels used (if applicable) and the sample sizes. The practical usefulness of the techniques is illustrated by observing the errors of the models in fitting the upper percentiles of the parent distribution. Two sets of air pollution data, namely hourly pollutant observations of B-scattering and nitrogen dioxide, from an urban airshed are used to examine the similarities and differences in fitting 2- and 3-parameter distributions where historical practice suggests there is a preference for the more parsimonious model.

ISSN:0266-4763    

DOI:10.1080/02664769200000039

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

Pair-wise matched case-control design is commonly used in epidemiological analysis for estimating odds ratios. In the most simplest situation, each subject is classified according to a binary outcome and the factor of interest being a two-level factor. Binary logistic models have beenfound to be very useful for studying such relationship. In our earlier studies we have shown that polytomous logistic model can be used for estimating odds ratios when the exposure of prime interest assumes multiple levels. In this paper, using the above model, we estimate the odds ratios for the possible levels of risk factor of interest adjusting for covariates which were notincluded in the matching process. An illustrative example is presented and discussed.

ISSN:0266-4763    

DOI:10.1080/02664769200000040

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

This paper is concerned with how standard estimation procedures perform in terms of eficiency for non-normal rounded data. Previous research has shown that the loss in eficiency due to rounding normal data is small. However, evidence from the non-normal distribution considered in this paper suggests, if rounding is coarse or the distribution is very skewed the loss in efficiency due to rounding can be considerable.

ISSN:0266-4763    

DOI:10.1080/02664769200000041

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

The problem of estimating the value of an x variable for a given proportion of an observed value of the y variable is consdered for a non-linear model. Asymptotic confidence limits are obtained and an application of the method is illustrated witreal data.

ISSN:0266-4763    

DOI:10.1080/02664769200000042

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

We examine the asymptotic distribution of, and give critical values for, a test related to Pearson's measure of skewness. The test detects the asymmetry of a continuous distribution about a specified median. Two sets of data are tested using our method.eabs:

ISSN:0266-4763    

DOI:10.1080/02664769200000043

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

Given three distinct lines (varieties or strains), say A, B and C, we can form three distinct three-way crosses (AB)C, (AC) B and (BC)A. The set of all possible three-way crosses VT = v(v — 1 )(v — 2)/2 among the given set of v lines is termed triallel crosses or a triallel mating design. As the number of lines v increases, the triallel crosses become too many to be accommodated within the resources of the breeder. One of the ways to overcome this situation is to take a sample of three-way crosses, called partial triallel crosses. Estimators for design and genetic components of variance have been developed based on Hinkelmann's model.

ISSN:0266-4763    

DOI:10.1080/02664769200000044

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

Minimization of the variance of the estimated slope of a response surface maximized over all points in the factor space is taken as the design criterion. Optimal designs under the criterion are derived for second-order polynomial regression over hypercubic regions.

ISSN:0266-4763    

DOI:10.1080/02664769200000045

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

For the analysis of square contingency tables with ordered categories, this paper introduces a simple symmetry model in which the expected frequency has an exponential form along every subdiagonal of the table. The model is applied to the data on unaided distance vision of 3168 pupils at elementary schools in Tokyo which were reported earlier by Tomizawa, and a result of interest is obtained.

ISSN:0266-4763    

DOI:10.1080/02664769200000046

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor

摘要:

When weights are assigned to a data matrix, as in the iterative least squares estimator of a generalized linear model, the condition of the data matrix is changed. In this paper a geometrical approach to studying the mechanisms which determine the changed condition is introduced. Specifically, it is found that in some cases strong multicollinearities can be weakened or eliminated by the weights while in other cases the weights can induce an ill-conditioning.

ISSN:0266-4763    

DOI:10.1080/02664769200000047

出版商:Carfax Publishing Company    

年代:1992

数据来源: Taylor