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141.
The authors propose new rank statistics for testing the white noise hypothesis in a time series. These statistics are Cramér‐von Mises and Kolmogorov‐Smirnov functionals of an empirical distribution function whose mean is related to a serial version of Kendall's tau through a linear transform. The authors determine the asymptotic behaviour of the underlying serial process and the large‐sample distribution of the proposed statistics under the null hypothesis of white noise. They also present simulation results showing the power of their tests.  相似文献   
142.
A closed form analytic expression for the Bell-Doksum Statistic is developed. The use of the generalized hypergeometric function to evaluate the expression is demonstrated, and a table of critical values for 2 n 25 is presented.  相似文献   
143.
144.
Nonparametric tests are proposed for the equality of two unknown p-variate distributions. Empirical probability measures are defined from samples from the two distributions and used to construct test statistics as the supremum of the absolute differences between empirical probabilities, the supremum being taken over all possible events. The test statistics are truly multivariate in not requiring the artificial ranking of multivariate observations, and they are distribution-free in the general p-variate case. Asymptotic null distributions are obtained. Powers of the proposed tests and a competitor are examined by Monte Carlo techniques.  相似文献   
145.
A necessary and sufficient condition for unbiasedness of the test of homogeneity of variances in normal samples is derived in a convenient form. In the case of two samples, it is shown that Bartlett's test is the only unbiased test of homogeneity of variances. A simple alternative proof of the unbiasedness of Bartlett's test in the general case is also provided.  相似文献   
146.
创新是知识经济时代的特征,是一国竞争力的主要源泉,专利授予量则是衡量一国创新状况的最好指标。在经济一体化的今天,一国的经济实力和该国的贸易状况有着密切的关系。通过EG协整检验、因果关系检验等方法,验证代表一国创新水平的专利尤其是发明专利对外贸出口的直接拉动效应。实证分析显示,在韩国,创新活动在增加出口方面扮演更重要的角色。这表明,一国竞争力的提高关键是自主创新能力的提升。  相似文献   
147.
本实验采用内隐联结测验(IAT),回避社会赞许效应等干扰因素,考察了当代大学生对于女性印象的内隐态度,发现他们更认同与现代女性形象即他们女性印象是积极地,独立自主的。且这种内隐认同态度不存在性别差异、城乡差异及文理科差异。  相似文献   
148.
On Reading Test     
There has been a long discussion over the construct validity of reading tests. In china's reading tests, multiple choice is the main test method in view of the4 long controversy over the validity of multiple choice, construct validation is called for to empirically test the hypothesized relationships between test scores and abilities. The national CET committee conducted a comprehensive validation study. As part of the project, the specialists studied the reading comprehension test' s validity by qualitative means, namely "introspective verbal reports". The analysis revealed that an overwhelming majority of the questions items were handled through "expected reading operations".  相似文献   
149.
One of the challenges in the design of confirmatory trials is to deal with uncertainties regarding the optimal target population for a novel drug. Adaptive enrichment designs (AED) which allow for a data-driven selection of one or more prespecified biomarker subpopulations at an interim analysis have been proposed in this setting but practical case studies of AEDs are still relatively rare. We present the design of an AED with a binary endpoint in the highly dynamic setting of cancer immunotherapy. The trial was initiated as a conventional trial in early triple-negative breast cancer but amended to an AED based on emerging data external to the trial suggesting that PD-L1 status could be a predictive biomarker. Operating characteristics are discussed including the concept of a minimal detectable difference, that is, the smallest observed treatment effect that would lead to a statistically significant result in at least one of the target populations at the interim or the final analysis, respectively, in the setting of AED.  相似文献   
150.
We review and compare existing methods for sample size calculation based on the logrank statistic and recommend the method of Lakatos for its accuracy and flexibility in allowing time-dependent rates of event, loss to follow-up, and noncompliance. We extend the Lakatos method to allow a general follow-up scheme, to handle non-inferiority tests, and to predict the number of events over calendar time. We apply the Lakatos method to the simple nonproportional hazard situation of delayed treatment effect to facilitate the comparison of different weighting methods and to evaluate the performance of the maximum combination tests. We use simulation studies to confirm the validity of the Lakatos method and its extensions.  相似文献   
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