共查询到12条相似文献,搜索用时 0 毫秒
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Fabio Corradi Giampietro Lago Federico M. Stefanini 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》2003,166(3):425-440
Summary. The evaluation of nuclear DNA evidence for identification purposes is performed here taking account of the uncertainty about population parameters. Graphical models are used to detail the hypotheses being debated in a trial with the aim of obtaining a directed acyclic graph. Graphs also clarify the set of evidence that contributes to population inferences and they also describe the conditional independence structure of DNA evidence. Numerical illustrations are provided by re-examining three case-studies taken from the literature. Our calculations of the weight of evidence differ from those given by the authors of case-studies in that they reveal more conservative values. 相似文献
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Richard Royall Tsung-Shan Tsou 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(2):391-404
Summary. The strength of statistical evidence is measured by the likelihood ratio. Two key performance properties of this measure are the probability of observing strong misleading evidence and the probability of observing weak evidence. For the likelihood function associated with a parametric statistical model, these probabilities have a simple large sample structure when the model is correct. Here we examine how that structure changes when the model fails. This leads to criteria for determining whether a given likelihood function is robust (continuing to perform satisfactorily when the model fails), and to a simple technique for adjusting both likelihoods and profile likelihoods to make them robust. We prove that the expected information in the robust adjusted likelihood cannot exceed the expected information in the likelihood function from a true model. We note that the robust adjusted likelihood is asymptotically fully efficient when the working model is correct, and we show that in some important examples this efficiency is retained even when the working model fails. In such cases the Bayes posterior probability distribution based on the adjusted likelihood is robust, remaining correct asymptotically even when the model for the observable random variable does not include the true distribution. Finally we note a link to standard frequentist methodology—in large samples the adjusted likelihood functions provide robust likelihood-based confidence intervals. 相似文献
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S. Landau I. C. Ellison-Wright E. T. Bullmore 《Journal of the Royal Statistical Society. Series C, Applied statistics》2004,53(1):63-82
Summary. Functional magnetic resonance imaging (FMRI) measures the physiological response of the human brain to experimentally controlled stimulation. In a periodically designed experiment it is of interest to test for a difference in the timing (phase shift) of the response between two anatomically distinct brain regions. We suggest two tests for an interregional difference in phase shift: one based on asymptotic theory and one based on bootstrapping. Whilst the two procedures differ in some of their assumptions, both tests rely on employing the large number of voxels (three-dimensional pixels) in non-activated brain regions to take account of spatial autocorrelation between voxelwise phase shift observations within the activated regions of interest. As an example we apply both tests, and their counterparts assuming spatial independence, to FMRI phase shift data that were acquired from a normal young woman during performance of a periodically designed covert verbal fluency task. We conclude that it is necessary to take account of spatial autocovariance between voxelwise FMRI time series parameter estimates such as the phase shift, and that the most promising way of achieving this is by modelling the spatial autocorrelation structure from a suitably defined base region of the image slice. 相似文献
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William C. Guenther 《The American statistician》2013,67(4):209-210
Approximations to the noncentral F distribution yield surprisingly accurate results for power and sample size problems arising from linear hypotheses about normal random variables. The approximations are easy to use with a desk (or hand-held) calculator that computes cumulative F probabilities. These approximations are particularly advantageous for testing the hypothesis that differences among the means are small against the alternative that the differences are large. 相似文献
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Nicholas Apergis Christina Christou James W. Saunoris 《Journal of applied statistics》2015,42(1):202-213
This study examines whether real interest rates exhibit changes in persistence for a panel of Organization of Economic Cooperation and Development countries. The findings show that for long-term real interest rates there are changes in persistence from I(0) to I(1). For short-term real interest rates, the results display the absence of changes in persistence, while under cross-sectional dependence there is only weak evidence of changes in persistence from I(1) to I(0). The evidence of changes in persistence when the direction is considered unknown is even weaker. 相似文献
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Federico Martellosio 《Econometric Reviews》2013,32(2):215-240
We show that for any sample size, any size of the test, and any weights matrix outside a small class of exceptions, there exists a positive measure set of regression spaces such that the power of the Cliff–Ord test vanishes as the autocorrelation increases in a spatial error model. This result extends to the tests that define the Gaussian power envelope of all invariant tests for residual spatial autocorrelation. In most cases, the regression spaces such that the problem occurs depend on the size of the test, but there also exist regression spaces such that the power vanishes regardless of the size. A characterization of such particularly hostile regression spaces is provided. 相似文献
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《Journal of Statistical Computation and Simulation》2012,82(3-4):307-313
Barnard (1963), Birnbaum (1974), and others have proposed exact inference procedures based on simulation. This article surveys existing results in this general area and fills several important holes, addressing philosophical problems and the matter of determining a simulation size. Applications to multiple comparisons, sequential analysis, and statistical consulting are discussed. 相似文献
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Summary We deal with double sampling plans by variables for a one-sided specification limit when the quality characteristic is normally
distributed with unknown standard deviation. An algorithm is presented that allows to calculate the OC of the sampling plans
proposed by Bowker and Goode (1952). We give several examples. Furthermore, it is shown that the algorithm carries over to
calculating the OC of the double-stage t-test.
The authors wish to thank Yvonne K?llner and Timor Saffary for technical support. 相似文献