排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
Xuming He 《统计学通讯:理论与方法》2013,42(10):3585-3594
A likelihood ratio test for discordancy in the sample is considered with slippage alternatives. It is shown for a wide class of univariate distributions that only the extreme observations in the sample need to be tested for discordancy. This result provides a firmer support to many commonly used discordancy tests that take only extreme observations as candidates. The problem of testing multiple discordant observations is also discussed. 相似文献
2.
Seymour Geisser 《Revue canadienne de statistique》1989,17(1):19-26
Using a Bayesian approach, unconditional and conditional predictive testing procedures are proposed for the detection of discordant observations for the translated exponential distribution in the presence of censored observations. 相似文献
3.
The only parametric model in current use for axial data from a rotationally symmetric bipolar or girdle distribution on the sphere is the Watson distribution. This paper develops methods for evaluating the model as a fit to data using graphical and formal goodness-of-fit tests, and tests of discordancy. 相似文献
4.
Nirpeksh Kumar 《Statistics》2013,47(1):184-190
An approach for testing multiple upper outliers with slippage alternative in an exponential sample, irrespective of origin, is discussed. The outlier detection procedure is based on a ratio of two estimates, obtained by the maximization of the two log-likelihood functions. One is the complete data log-likelihood and the other is its conditional expectation, given the regular observations. The exact null distribution of the test statistic is derived and no new table for critical values is required. A simulation study is also carried out to compare the performance of the test with the earlier work. 相似文献
5.
Outliers can occur as readily in samples from the finite populations (e.g. in sample surveys) as in samples from infinite populations. However, in the vast literature on outliers there is almost no mention of outlier tests for data from sample surveys. We examine the behaviour of some standard outlier test statistics for infinite populations when these are applied to finite populations, examining their properties by extensive simulation studies. Some anomalous results are obtained Nsuggesting a fundamental difficulty in testing outliers for the finite population case. 相似文献
6.
Vic Barnett 《Australian & New Zealand Journal of Statistics》1983,25(1):64-75
The study of multivariate outliers raises many problems of definition, principle and manipulation. Well-authenticated tests of discordancy exist only for the multivariate normal distribution. Detection of outliers in non-normal distributions involves the adoption of appropriate criteria to represent 'extremeness' of observations in a sample; corresponding tests of discordancy usually require tedious, or even intractable, distributional and computational manipulations. A class of transformations of the data is considered with a view of transferring some of the familiar and desirable features of discordancy tests for normal samples to non-normal situations. 相似文献
7.
《Journal of Statistical Computation and Simulation》2012,82(3):463-473
Recently, Sanjel and Balakrishnan [A Laguerre Polynomial Approximation for a goodness-of-fit test for exponential distribution based on progressively censored data, J. Stat. Comput. Simul. 78 (2008), pp. 503–513] proposed the use of Laguerre orthogonal polynomials for a goodness-of-fit test for the exponential distribution based on progressively censored data. In this paper, we use Jacobi and Laguerre orthogonal polynomials in order to obtain density approximants for some test statistics useful in testing for outliers in gamma and exponential samples. We first obtain the exact moments of the statistics and then the density approximants, based on these moments, are expressed in terms of Jacobi and Laguerre polynomials. A comparative study is carried out of the critical values obtained by using the proposed methods to the corresponding results given by Barnett and Lewis [Outliers in Statistical Data, 3rd ed., John Wiley & Sons, New York, 1993]. This reveals that the proposed techniques provide very accurate approximations to the distributions. Finally, we present some numerical examples to illustrate the proposed approximations. Monte Carlo simulations suggest that the proposed approximate densities are very accurate. 相似文献
8.
Due to wide applicability and simplicity, the exponential distribution is the most commonly used distribution in reliability engineering and other life testing experiments. In this paper a test statistic for testing upper and lower outliers simultaneously in an exponential sample is proposed. However, the distribution of test statistic under the alternative is rather intricate, the null distribution is derived and critical values are obtained. A simulation study is also carried out to compare the performance of test and is found that the test based on this statistic is more powerful than the other two selected tests. 相似文献
9.
A.C. Kimber 《统计学通讯:模拟与计算》2013,42(3):1055-1072
The problem of discordancy testing for an upper and lower outlier pair in a sample from a gamma distribution with known shape is considered. Three statistics are investigated: the well-known extremal quotient and two likelihood-based procedures. Approximations t o the null distributions of the statistics are obtained where appropriate. The non-null properties are investigated by sensitivity contours and simulation. 相似文献
10.
S. Lalitha 《Journal of applied statistics》2012,39(6):1323-1330
In this paper, a test statistic for testing upper outliers with a slippage alternative, in an exponential sample is proposed. No tables for critical values are required as they can be calculated easily for any sample size. A simulation study is also carried out to compare the performance of the test with the maximum likelihood ratio test and other existing tests. 相似文献