Simulation Statistic
Mostrando 13-24 de 33 artigos, teses e dissertações.
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13. Testes de significancia repetidos em analise de sobrevivencia
The main objective of this work is to elaborate a detailed exposition of the theory of repeated significance tests, with particular emphasis on non parametric tests used in Survival Analysis. A second objective is to study and use in applications the somehow new Weighted Kaplan Meier statistic that was created to compare survival in two populations. This sta
Publicado em: 2002
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14. Uma analise dos filtros condicionais seletores de posição e sua aplicação na restauração de imagens digitais
In this work, a class of nonlinear filters called rank conditioned rank selection (RCRS) filters is studied and developed. The RCRS filters are analyzed within the general framework of rank selection (RS) filters, which are filters constrained to output an order statistic from the observation set. Many filters previously proposed (e.g. median filter, center
Publicado em: 2000
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15. An Entropy-Based Statistic for Genomewide Association Studies
Efficient genotyping methods and the availability of a large collection of single-nucleotide polymorphisms provide valuable tools for genetic studies of human disease. The standard χ2 statistic for case-control studies, which uses a linear function of allele frequencies, has limited power when the number of marker loci is large. We introduce a novel test st
American Society of Human Genetics.
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16. Analysis of variations in mortality rates with small numbers.
OBJECTIVE. We present a Monte Carlo technique to evaluate if observed mortality rates differ from model-predicted rates for situations when the number of deaths is small. DATA SOURCES. We used Medicare hospital claims and model-predicted mortality rates from the Health Care Financing Administration (HCFA) for the 169 acute care hospitals in Georgia. The HCFA
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17. A Statistical Test of a Neutral Model Using the Dynamics of Cytonuclear Disequilibria
In this paper we use cytonuclear disequilibria to test the neutrality of mtDNA markers. The data considered here involve sample frequencies of cytonuclear genotypes subject to both statistical sampling variation as well as genetic sampling variation. First, we obtain the dynamics of the sample cytonuclear disequilibria assuming random drift alone as the sour
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18. Precision Mapping of Quantitative Trait Loci
Adequate separation of effects of possible multiple linked quantitative trait loci (QTLs) on mapping QTLs is the key to increasing the precision of QTL mapping. A new method of QTL mapping is proposed and analyzed in this paper by combining interval mapping with multiple regression. The basis of the proposed method is an interval test in which the test stati
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19. Genotypic Diversity: Estimation and Prediction in Samples
We show that a commonly used statistic of genotypic diversity can be used to reflect one form of deviation from panmixia, viz. clonal reproduction, by comparing observed and predicted sample statistics. The characteristics of the statistic, in particular its relationship with population genotypic diversity, are formalised and a method of predicting the genot
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20. The use of a Kolmogorov--Smirnov type statistic in testing hypotheses about seasonal variation.
This paper presents a non-parametric method for testing departures from a uniform seasonal variation in incidence of disease. The method may be used either with exact dates of incidence when they are available or with monthly totals. It is equally valid for sinusoidal and non-sinusoidal departures from uniformity. A simulation study shows it to be much more
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21. Use of Closely Related Affected Individuals for the Genetic Study of Complex Diseases in Founder Populations
We propose a method, the maximum identity length contrast (MILC) statistic, to locate genetic risk factors for complex diseases in founder populations. The MILC approach compares the identity length of parental haplotypes that are transmitted to affected offspring with the identity length of those that are not transmitted to affected offspring. Initially, th
The American Society of Human Genetics.
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22. Maximum Likelihood Analysis of Rare Binary Traits under Different Modes of Inheritance
Maximum likelihood methodology was applied to determine the mode of inheritance of rare binary traits with data structures typical for swine populations. The genetic models considered included a monogenic, a digenic, a polygenic, and three mixed polygenic and major gene models. The main emphasis was on the detection of major genes acting on a polygenic backg
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23. Statistics for Nonparametric Linkage Analysis of X-Linked Traits in General Pedigrees
We have compared the power of several allele-sharing statistics for “nonparametric” linkage analysis of X-linked traits in nuclear families and extended pedigrees. Our rationale was that, although several of these statistics have been implemented in popular software packages, there has been no formal evaluation of their relative power. Here, we evaluate
The American Society of Human Genetics.
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24. A Transmission/Disequilibrium Test That Allows for Genotyping Errors in the Analysis of Single-Nucleotide Polymorphism Data
The present study assesses the effects of genotyping errors on the type I error rate of a particular transmission/disequilibrium test (TDTstd), which assumes that data are errorless, and introduces a new transmission/disequilibrium test (TDTae) that allows for random genotyping errors. We evaluate the type I error rate and power of the TDTae under a variety
The American Society of Human Genetics.